/*-------------------------------------------------------------------------
 *
 * analyze.c
 *	  transform the parse tree into a query tree
 *
 * Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 *	$Header: /cvsroot/pgsql/src/backend/parser/analyze.c,v 1.181 2001/02/15 01:10:28 tgl Exp $
 *
 *-------------------------------------------------------------------------
 */

#include "postgres.h"

#include "access/heapam.h"
#include "catalog/catname.h"
#include "catalog/pg_index.h"
#include "catalog/pg_type.h"
#include "nodes/makefuncs.h"
#include "parser/analyze.h"
#include "parser/parse.h"
#include "parser/parsetree.h"
#include "parser/parse_agg.h"
#include "parser/parse_clause.h"
#include "parser/parse_coerce.h"
#include "parser/parse_relation.h"
#include "parser/parse_target.h"
#include "parser/parse_type.h"
#include "rewrite/rewriteManip.h"
#include "utils/builtins.h"
#include "utils/fmgroids.h"
#include "utils/relcache.h"
#include "utils/syscache.h"

#ifdef MULTIBYTE
#include "mb/pg_wchar.h"
#endif

static Query *transformStmt(ParseState *pstate, Node *stmt);
static Query *transformDeleteStmt(ParseState *pstate, DeleteStmt *stmt);
static Query *transformInsertStmt(ParseState *pstate, InsertStmt *stmt);
static Query *transformIndexStmt(ParseState *pstate, IndexStmt *stmt);
static Query *transformExtendStmt(ParseState *pstate, ExtendStmt *stmt);
static Query *transformRuleStmt(ParseState *query, RuleStmt *stmt);
static Query *transformSelectStmt(ParseState *pstate, SelectStmt *stmt);
static Query *transformSetOperationStmt(ParseState *pstate, SelectStmt *stmt);
static Node *transformSetOperationTree(ParseState *pstate, SelectStmt *stmt);
static Query *transformUpdateStmt(ParseState *pstate, UpdateStmt *stmt);
static Query *transformCreateStmt(ParseState *pstate, CreateStmt *stmt);
static Query *transformAlterTableStmt(ParseState *pstate, AlterTableStmt *stmt);

static List *getSetColTypes(ParseState *pstate, Node *node);
static void transformForUpdate(Query *qry, List *forUpdate);
static void transformFkeyGetPrimaryKey(FkConstraint *fkconstraint);
static void transformConstraintAttrs(List *constraintList);
static void transformColumnType(ParseState *pstate, ColumnDef *column);
static void transformFkeyCheckAttrs(FkConstraint *fkconstraint);

static void release_pstate_resources(ParseState *pstate);
static FromExpr *makeFromExpr(List *fromlist, Node *quals);

/* kluge to return extra info from transformCreateStmt() */
static List *extras_before;
static List *extras_after;


/*
 * parse_analyze -
 *	  analyze a raw parse tree and transform it to Query form.
 *
 * The result is a List of Query nodes (we need a list since some commands
 * produce multiple Queries).  Optimizable statements require considerable
 * transformation, while many utility-type statements are simply hung off
 * a dummy CMD_UTILITY Query node.
 */
List *
parse_analyze(Node *parseTree, ParseState *parentParseState)
{
	List	   *result = NIL;
	ParseState *pstate = make_parsestate(parentParseState);
	Query	   *query;

	extras_before = extras_after = NIL;

	query = transformStmt(pstate, parseTree);
	release_pstate_resources(pstate);

	while (extras_before != NIL)
	{
		result = lappend(result,
						 transformStmt(pstate, lfirst(extras_before)));
		release_pstate_resources(pstate);
		extras_before = lnext(extras_before);
	}

	result = lappend(result, query);

	while (extras_after != NIL)
	{
		result = lappend(result,
						 transformStmt(pstate, lfirst(extras_after)));
		release_pstate_resources(pstate);
		extras_after = lnext(extras_after);
	}

	pfree(pstate);

	return result;
}

static void
release_pstate_resources(ParseState *pstate)
{
	if (pstate->p_target_relation != NULL)
		heap_close(pstate->p_target_relation, NoLock);
	pstate->p_target_relation = NULL;
	pstate->p_target_rangetblentry = NULL;
}

/*
 * transformStmt -
 *	  transform a Parse tree into a Query tree.
 */
static Query *
transformStmt(ParseState *pstate, Node *parseTree)
{
	Query	   *result = NULL;

	switch (nodeTag(parseTree))
	{
			/*------------------------
			 *	Non-optimizable statements
			 *------------------------
			 */
		case T_CreateStmt:
			result = transformCreateStmt(pstate, (CreateStmt *) parseTree);
			break;

		case T_IndexStmt:
			result = transformIndexStmt(pstate, (IndexStmt *) parseTree);
			break;

		case T_ExtendStmt:
			result = transformExtendStmt(pstate, (ExtendStmt *) parseTree);
			break;

		case T_RuleStmt:
			result = transformRuleStmt(pstate, (RuleStmt *) parseTree);
			break;

		case T_ViewStmt:
			{
				ViewStmt   *n = (ViewStmt *) parseTree;

				n->query = transformStmt(pstate, (Node *) n->query);

				/*
				 * If a list of column names was given, run through and
				 * insert these into the actual query tree. - thomas
				 * 2000-03-08
				 */
				if (n->aliases != NIL)
				{
					int			i;
					List	   *targetList = n->query->targetList;

					if (length(targetList) < length(n->aliases))
						elog(ERROR, "CREATE VIEW specifies %d columns"
							 " but only %d columns are present",
							 length(targetList), length(n->aliases));

					for (i = 0; i < length(n->aliases); i++)
					{
						Ident	   *id;
						TargetEntry *te;
						Resdom	   *rd;

						id = nth(i, n->aliases);
						Assert(IsA(id, Ident));
						te = nth(i, targetList);
						Assert(IsA(te, TargetEntry));
						rd = te->resdom;
						Assert(IsA(rd, Resdom));
						rd->resname = pstrdup(id->name);
					}
				}
				result = makeNode(Query);
				result->commandType = CMD_UTILITY;
				result->utilityStmt = (Node *) n;
			}
			break;

		case T_ExplainStmt:
			{
				ExplainStmt *n = (ExplainStmt *) parseTree;

				result = makeNode(Query);
				result->commandType = CMD_UTILITY;
				n->query = transformStmt(pstate, (Node *) n->query);
				result->utilityStmt = (Node *) parseTree;
			}
			break;

		case T_AlterTableStmt:
			result = transformAlterTableStmt(pstate, (AlterTableStmt *) parseTree);
			break;

			/*------------------------
			 *	Optimizable statements
			 *------------------------
			 */
		case T_InsertStmt:
			result = transformInsertStmt(pstate, (InsertStmt *) parseTree);
			break;

		case T_DeleteStmt:
			result = transformDeleteStmt(pstate, (DeleteStmt *) parseTree);
			break;

		case T_UpdateStmt:
			result = transformUpdateStmt(pstate, (UpdateStmt *) parseTree);
			break;

		case T_SelectStmt:
			if (((SelectStmt *) parseTree)->op == SETOP_NONE)
				result = transformSelectStmt(pstate,
											 (SelectStmt *) parseTree);
			else
				result = transformSetOperationStmt(pstate,
												   (SelectStmt *) parseTree);
			break;

		default:

			/*
			 * other statements don't require any transformation-- just
			 * return the original parsetree, yea!
			 */
			result = makeNode(Query);
			result->commandType = CMD_UTILITY;
			result->utilityStmt = (Node *) parseTree;
			break;
	}
	return result;
}

/*
 * transformDeleteStmt -
 *	  transforms a Delete Statement
 */
static Query *
transformDeleteStmt(ParseState *pstate, DeleteStmt *stmt)
{
	Query	   *qry = makeNode(Query);
	Node	   *qual;

	qry->commandType = CMD_DELETE;

	/* set up range table with just the result rel */
	qry->resultRelation = setTargetTable(pstate, stmt->relname,
										 interpretInhOption(stmt->inhOpt),
										 true);

	qry->distinctClause = NIL;

	/* fix where clause */
	qual = transformWhereClause(pstate, stmt->whereClause);

	/* done building the range table and jointree */
	qry->rtable = pstate->p_rtable;
	qry->jointree = makeFromExpr(pstate->p_joinlist, qual);

	qry->hasSubLinks = pstate->p_hasSubLinks;
	qry->hasAggs = pstate->p_hasAggs;
	if (pstate->p_hasAggs)
		parseCheckAggregates(pstate, qry, qual);

	return qry;
}

/*
 * transformInsertStmt -
 *	  transform an Insert Statement
 */
static Query *
transformInsertStmt(ParseState *pstate, InsertStmt *stmt)
{
	Query	   *qry = makeNode(Query);
	List	   *sub_rtable;
	List	   *sub_namespace;
	List	   *icolumns;
	List	   *attrnos;
	List	   *attnos;
	int			numuseratts;
	List	   *tl;
	TupleDesc	rd_att;

	qry->commandType = CMD_INSERT;
	pstate->p_is_insert = true;

	/*
	 * If a non-nil rangetable/namespace was passed in, and we are doing
	 * INSERT/SELECT, arrange to pass the rangetable/namespace down to the
	 * SELECT.  This can only happen if we are inside a CREATE RULE,
	 * and in that case we want the rule's OLD and NEW rtable entries to
	 * appear as part of the SELECT's rtable, not as outer references for
	 * it.  (Kluge!)  The SELECT's joinlist is not affected however.
	 * We must do this before adding the target table to the INSERT's rtable.
	 */
	if (stmt->selectStmt)
	{
		sub_rtable = pstate->p_rtable;
		pstate->p_rtable = NIL;
		sub_namespace = pstate->p_namespace;
		pstate->p_namespace = NIL;
	}
	else
	{
		sub_rtable = NIL;		/* not used, but keep compiler quiet */
		sub_namespace = NIL;
	}

	/*
	 * Must get write lock on INSERT target table before scanning SELECT,
	 * else we will grab the wrong kind of initial lock if the target
	 * table is also mentioned in the SELECT part.  Note that the target
	 * table is not added to the joinlist or namespace.
	 */
	qry->resultRelation = setTargetTable(pstate, stmt->relname,
										 false, false);

	/*
	 * Is it INSERT ... SELECT or INSERT ... VALUES?
	 */
	if (stmt->selectStmt)
	{
		ParseState *sub_pstate = make_parsestate(pstate->parentParseState);
		Query  *selectQuery;
		RangeTblEntry *rte;
		RangeTblRef *rtr;

		/*
		 * Process the source SELECT.
		 *
		 * It is important that this be handled just like a standalone SELECT;
		 * otherwise the behavior of SELECT within INSERT might be different
		 * from a stand-alone SELECT. (Indeed, Postgres up through 6.5 had
		 * bugs of just that nature...)
		 */
		sub_pstate->p_rtable = sub_rtable;
		sub_pstate->p_namespace = sub_namespace;

		selectQuery = transformStmt(sub_pstate, stmt->selectStmt);

		release_pstate_resources(sub_pstate);
		pfree(sub_pstate);

		Assert(IsA(selectQuery, Query));
		Assert(selectQuery->commandType == CMD_SELECT);
		if (selectQuery->into || selectQuery->isPortal)
			elog(ERROR, "INSERT ... SELECT may not specify INTO");
		/*
		 * Make the source be a subquery in the INSERT's rangetable,
		 * and add it to the INSERT's joinlist.
		 */
		rte = addRangeTableEntryForSubquery(pstate,
											selectQuery,
											makeAttr("*SELECT*", NULL),
											true);
		rtr = makeNode(RangeTblRef);
		/* assume new rte is at end */
		rtr->rtindex = length(pstate->p_rtable);
		Assert(rte == rt_fetch(rtr->rtindex, pstate->p_rtable));
		pstate->p_joinlist = lappend(pstate->p_joinlist, rtr);
		/*
		 * Generate a targetlist for the INSERT that selects all
		 * the non-resjunk columns from the subquery.  (We need this to
		 * be separate from the subquery's tlist because we may add
		 * columns, insert datatype coercions, etc.)
		 *
		 * HACK: constants in the INSERT's targetlist are copied up as-is
		 * rather than being referenced as subquery outputs.  This is mainly
		 * to ensure that when we try to coerce them to the target column's
		 * datatype, the right things happen for UNKNOWN constants.
		 * Otherwise this fails:
		 *		INSERT INTO foo SELECT 'bar', ... FROM baz
		 */
		qry->targetList = NIL;
		foreach(tl, selectQuery->targetList)
		{
			TargetEntry *tle = (TargetEntry *) lfirst(tl);
			Resdom	   *resnode = tle->resdom;
			Node	   *expr;

			if (resnode->resjunk)
				continue;
			if (tle->expr && IsA(tle->expr, Const))
				expr = tle->expr;
			else
				expr = (Node *) makeVar(rtr->rtindex,
										resnode->resno,
										resnode->restype,
										resnode->restypmod,
										0);
			resnode = copyObject(resnode);
			resnode->resno = (AttrNumber) pstate->p_last_resno++;
			qry->targetList = lappend(qry->targetList,
									  makeTargetEntry(resnode, expr));
		}
	}
	else
	{
		/*
		 * For INSERT ... VALUES, transform the given list of values
		 * to form a targetlist for the INSERT.
		 */
		qry->targetList = transformTargetList(pstate, stmt->targetList);
	}

	/*
	 * Now we are done with SELECT-like processing, and can get on with
	 * transforming the target list to match the INSERT target columns.
	 */

	/* Prepare to assign non-conflicting resnos to resjunk attributes */
	if (pstate->p_last_resno <= pstate->p_target_relation->rd_rel->relnatts)
		pstate->p_last_resno = pstate->p_target_relation->rd_rel->relnatts + 1;

	/* Validate stmt->cols list, or build default list if no list given */
	icolumns = checkInsertTargets(pstate, stmt->cols, &attrnos);

	/*
	 * Prepare columns for assignment to target table.
	 */
	numuseratts = 0;
	attnos = attrnos;
	foreach(tl, qry->targetList)
	{
		TargetEntry *tle = (TargetEntry *) lfirst(tl);
		Ident	   *id;

		Assert(!tle->resdom->resjunk);
		if (icolumns == NIL || attnos == NIL)
			elog(ERROR, "INSERT has more expressions than target columns");
		id = (Ident *) lfirst(icolumns);
		updateTargetListEntry(pstate, tle, id->name, lfirsti(attnos),
							  id->indirection);
		numuseratts++;
		icolumns = lnext(icolumns);
		attnos = lnext(attnos);
	}

	/*
	 * It is possible that the targetlist has fewer entries than were in
	 * the columns list.  We do not consider this an error (perhaps we
	 * should, if the columns list was explictly given?).  We must
	 * truncate the attrnos list to only include the attrs actually
	 * provided, else we will fail to apply defaults for them below.
	 */
	if (icolumns != NIL)
		attrnos = ltruncate(numuseratts, attrnos);

	/*
	 * Add targetlist items to assign DEFAULT values to any columns that
	 * have defaults and were not assigned to by the user.
	 *
	 * XXX wouldn't it make more sense to do this further downstream, after
	 * the rule rewriter?  As is, altering a column default will not change
	 * the behavior of INSERTs in already-defined rules.
	 */
	rd_att = pstate->p_target_relation->rd_att;
	if (rd_att->constr && rd_att->constr->num_defval > 0)
	{
		Form_pg_attribute *att = rd_att->attrs;
		AttrDefault *defval = rd_att->constr->defval;
		int			ndef = rd_att->constr->num_defval;

		while (--ndef >= 0)
		{
			AttrNumber	attrno = defval[ndef].adnum;
			Form_pg_attribute thisatt = att[attrno - 1];
			TargetEntry *te;

			if (intMember((int) attrno, attrnos))
				continue;		/* there was a user-specified value */

			/*
			 * No user-supplied value, so add a targetentry with DEFAULT
			 * expr and correct data for the target column.
			 */
			te = makeTargetEntry(
								 makeResdom(attrno,
											thisatt->atttypid,
											thisatt->atttypmod,
									  pstrdup(NameStr(thisatt->attname)),
											false),
								 stringToNode(defval[ndef].adbin));
			qry->targetList = lappend(qry->targetList, te);

			/*
			 * Make sure the value is coerced to the target column type
			 * (might not be right type if it's not a constant!)
			 */
			updateTargetListEntry(pstate, te, te->resdom->resname, attrno,
								  NIL);
		}
	}

	/* done building the range table and jointree */
	qry->rtable = pstate->p_rtable;
	qry->jointree = makeFromExpr(pstate->p_joinlist, NULL);

	qry->hasSubLinks = pstate->p_hasSubLinks;
	qry->hasAggs = pstate->p_hasAggs;
	if (pstate->p_hasAggs)
		parseCheckAggregates(pstate, qry, NULL);

	return qry;
}

/*
 *	makeObjectName()
 *
 *	Create a name for an implicitly created index, sequence, constraint, etc.
 *
 *	The parameters are: the original table name, the original field name, and
 *	a "type" string (such as "seq" or "pkey").	The field name and/or type
 *	can be NULL if not relevant.
 *
 *	The result is a palloc'd string.
 *
 *	The basic result we want is "name1_name2_type", omitting "_name2" or
 *	"_type" when those parameters are NULL.  However, we must generate
 *	a name with less than NAMEDATALEN characters!  So, we truncate one or
 *	both names if necessary to make a short-enough string.	The type part
 *	is never truncated (so it had better be reasonably short).
 *
 *	To reduce the probability of collisions, we might someday add more
 *	smarts to this routine, like including some "hash" characters computed
 *	from the truncated characters.	Currently it seems best to keep it simple,
 *	so that the generated names are easily predictable by a person.
 */
static char *
makeObjectName(char *name1, char *name2, char *typename)
{
	char	   *name;
	int			overhead = 0;	/* chars needed for type and underscores */
	int			availchars;		/* chars available for name(s) */
	int			name1chars;		/* chars allocated to name1 */
	int			name2chars;		/* chars allocated to name2 */
	int			ndx;

	name1chars = strlen(name1);
	if (name2)
	{
		name2chars = strlen(name2);
		overhead++;				/* allow for separating underscore */
	}
	else
		name2chars = 0;
	if (typename)
		overhead += strlen(typename) + 1;

	availchars = NAMEDATALEN - 1 - overhead;

	/*
	 * If we must truncate,  preferentially truncate the longer name. This
	 * logic could be expressed without a loop, but it's simple and
	 * obvious as a loop.
	 */
	while (name1chars + name2chars > availchars)
	{
		if (name1chars > name2chars)
			name1chars--;
		else
			name2chars--;
	}

#ifdef MULTIBYTE
	if (name1)
		name1chars = pg_mbcliplen(name1, name1chars, name1chars);
	if (name2)
		name2chars = pg_mbcliplen(name2, name2chars, name2chars);
#endif

	/* Now construct the string using the chosen lengths */
	name = palloc(name1chars + name2chars + overhead + 1);
	strncpy(name, name1, name1chars);
	ndx = name1chars;
	if (name2)
	{
		name[ndx++] = '_';
		strncpy(name + ndx, name2, name2chars);
		ndx += name2chars;
	}
	if (typename)
	{
		name[ndx++] = '_';
		strcpy(name + ndx, typename);
	}
	else
		name[ndx] = '\0';

	return name;
}

static char *
CreateIndexName(char *table_name, char *column_name,
				char *label, List *indices)
{
	int			pass = 0;
	char	   *iname = NULL;
	List	   *ilist;
	char		typename[NAMEDATALEN];

	/*
	 * The type name for makeObjectName is label, or labelN if that's
	 * necessary to prevent collisions among multiple indexes for the same
	 * table.  Note there is no check for collisions with already-existing
	 * indexes, only among the indexes we're about to create now; this ought
	 * to be improved someday.
	 */
	strcpy(typename, label);

	for (;;)
	{
		iname = makeObjectName(table_name, column_name, typename);

		foreach(ilist, indices)
		{
			IndexStmt  *index = lfirst(ilist);

			if (index->idxname != NULL &&
				strcmp(iname, index->idxname) == 0)
				break;
		}
		/* ran through entire list? then no name conflict found so done */
		if (ilist == NIL)
			break;

		/* found a conflict, so try a new name component */
		pfree(iname);
		sprintf(typename, "%s%d", label, ++pass);
	}

	return iname;
}

/*
 * transformCreateStmt -
 *	  transforms the "create table" statement
 *	  SQL92 allows constraints to be scattered all over, so thumb through
 *	   the columns and collect all constraints into one place.
 *	  If there are any implied indices (e.g. UNIQUE or PRIMARY KEY)
 *	   then expand those into multiple IndexStmt blocks.
 *	  - thomas 1997-12-02
 */
static Query *
transformCreateStmt(ParseState *pstate, CreateStmt *stmt)
{
	Query	   *q;
	List	   *elements;
	Node	   *element;
	List	   *columns;
	List	   *dlist;
	ColumnDef  *column;
	List	   *constraints,
			   *clist;
	Constraint *constraint;
	List	   *fkconstraints,	/* List of FOREIGN KEY constraints to */
			   *fkclist;		/* add finally */
	FkConstraint *fkconstraint;
	List	   *keys;
	Ident	   *key;
	List	   *blist = NIL;	/* "before list" of things to do before
								 * creating the table */
	List	   *ilist = NIL;	/* "index list" of things to do after
								 * creating the table */
	IndexStmt  *index,
			   *pkey = NULL;
	IndexElem  *iparam;
	bool		saw_nullable;

	q = makeNode(Query);
	q->commandType = CMD_UTILITY;

	fkconstraints = NIL;
	constraints = stmt->constraints;
	columns = NIL;
	dlist = NIL;

	/*
	 * Run through each primary element in the table creation clause
	 */
	foreach(elements, stmt->tableElts)
	{
		element = lfirst(elements);
		switch (nodeTag(element))
		{
			case T_ColumnDef:
				column = (ColumnDef *) element;
				columns = lappend(columns, column);

				transformColumnType(pstate, column);

				/* Special case SERIAL type? */
				if (column->is_sequence)
				{
					char	   *sname;
					char	   *qstring;
					A_Const    *snamenode;
					FuncCall   *funccallnode;
					CreateSeqStmt *sequence;

					/*
					 * Create appropriate constraints for SERIAL.  We do
					 * this in full, rather than shortcutting, so that we
					 * will detect any conflicting constraints the user
					 * wrote (like a different DEFAULT).
					 */
					sname = makeObjectName(stmt->relname, column->colname,
										   "seq");

					/*
					 * Create an expression tree representing the function
					 * call  nextval('"sequencename"')
					 */
					qstring = palloc(strlen(sname) + 2 + 1);
					sprintf(qstring, "\"%s\"", sname);
					snamenode = makeNode(A_Const);
					snamenode->val.type = T_String;
					snamenode->val.val.str = qstring;
					funccallnode = makeNode(FuncCall);
					funccallnode->funcname = "nextval";
					funccallnode->args = makeList1(snamenode);
					funccallnode->agg_star = false;
					funccallnode->agg_distinct = false;

					constraint = makeNode(Constraint);
					constraint->contype = CONSTR_DEFAULT;
					constraint->name = sname;
					constraint->raw_expr = (Node *) funccallnode;
					constraint->cooked_expr = NULL;
					constraint->keys = NIL;
					column->constraints = lappend(column->constraints,
												  constraint);

					constraint = makeNode(Constraint);
					constraint->contype = CONSTR_UNIQUE;
					constraint->name = NULL; /* assign later */
					column->constraints = lappend(column->constraints,
												  constraint);

					constraint = makeNode(Constraint);
					constraint->contype = CONSTR_NOTNULL;
					column->constraints = lappend(column->constraints,
												  constraint);

					sequence = makeNode(CreateSeqStmt);
					sequence->seqname = pstrdup(sname);
					sequence->options = NIL;

					elog(NOTICE, "CREATE TABLE will create implicit sequence '%s' for SERIAL column '%s.%s'",
					  sequence->seqname, stmt->relname, column->colname);

					blist = lappend(blist, sequence);
				}

				/* Process column constraints, if any... */
				transformConstraintAttrs(column->constraints);

				saw_nullable = false;

				foreach(clist, column->constraints)
				{
					constraint = lfirst(clist);

					/* ----------
					 * If this column constraint is a FOREIGN KEY
					 * constraint, then we fill in the current attributes
					 * name and throw it into the list of FK constraints
					 * to be processed later.
					 * ----------
					 */
					if (IsA(constraint, FkConstraint))
					{
						Ident	   *id = makeNode(Ident);

						id->name = column->colname;
						id->indirection = NIL;
						id->isRel = false;

						fkconstraint = (FkConstraint *) constraint;
						fkconstraint->fk_attrs = makeList1(id);

						fkconstraints = lappend(fkconstraints, constraint);
						continue;
					}

					switch (constraint->contype)
					{
						case CONSTR_NULL:
							if (saw_nullable && column->is_not_null)
								elog(ERROR, "CREATE TABLE/(NOT) NULL conflicting declaration"
									 " for '%s.%s'", stmt->relname, column->colname);
							column->is_not_null = FALSE;
							saw_nullable = true;
							break;

						case CONSTR_NOTNULL:
							if (saw_nullable && !column->is_not_null)
								elog(ERROR, "CREATE TABLE/(NOT) NULL conflicting declaration"
									 " for '%s.%s'", stmt->relname, column->colname);
							column->is_not_null = TRUE;
							saw_nullable = true;
							break;

						case CONSTR_DEFAULT:
							if (column->raw_default != NULL)
								elog(ERROR, "CREATE TABLE/DEFAULT multiple values specified"
									 " for '%s.%s'", stmt->relname, column->colname);
							column->raw_default = constraint->raw_expr;
							Assert(constraint->cooked_expr == NULL);
							break;

						case CONSTR_PRIMARY:
							if (constraint->name == NULL)
								constraint->name = makeObjectName(stmt->relname, NULL, "pkey");
							if (constraint->keys == NIL)
							{
								key = makeNode(Ident);
								key->name = pstrdup(column->colname);
								constraint->keys = makeList1(key);
							}
							dlist = lappend(dlist, constraint);
							break;

						case CONSTR_UNIQUE:
							if (constraint->name == NULL)
								constraint->name = makeObjectName(stmt->relname, column->colname, "key");
							if (constraint->keys == NIL)
							{
								key = makeNode(Ident);
								key->name = pstrdup(column->colname);
								constraint->keys = makeList1(key);
							}
							dlist = lappend(dlist, constraint);
							break;

						case CONSTR_CHECK:
							if (constraint->name == NULL)
								constraint->name = makeObjectName(stmt->relname, column->colname, NULL);
							constraints = lappend(constraints, constraint);
							break;

						case CONSTR_ATTR_DEFERRABLE:
						case CONSTR_ATTR_NOT_DEFERRABLE:
						case CONSTR_ATTR_DEFERRED:
						case CONSTR_ATTR_IMMEDIATE:
							/* transformConstraintAttrs took care of these */
							break;

						default:
							elog(ERROR, "parser: unrecognized constraint (internal error)");
							break;
					}
				}
				break;

			case T_Constraint:
				constraint = (Constraint *) element;
				switch (constraint->contype)
				{
					case CONSTR_PRIMARY:
						if (constraint->name == NULL)
							constraint->name = makeObjectName(stmt->relname, NULL, "pkey");
						dlist = lappend(dlist, constraint);
						break;

					case CONSTR_UNIQUE:
						dlist = lappend(dlist, constraint);
						break;

					case CONSTR_CHECK:
						constraints = lappend(constraints, constraint);
						break;

					case CONSTR_NULL:
					case CONSTR_NOTNULL:
					case CONSTR_DEFAULT:
					case CONSTR_ATTR_DEFERRABLE:
					case CONSTR_ATTR_NOT_DEFERRABLE:
					case CONSTR_ATTR_DEFERRED:
					case CONSTR_ATTR_IMMEDIATE:
						elog(ERROR, "parser: illegal context for constraint (internal error)");
						break;

					default:
						elog(ERROR, "parser: unrecognized constraint (internal error)");
						break;
				}
				break;

			case T_FkConstraint:
				/* ----------
				 * Table level FOREIGN KEY constraints are already complete.
				 * Just remember for later.
				 * ----------
				 */
				fkconstraints = lappend(fkconstraints, element);
				break;

			default:
				elog(ERROR, "parser: unrecognized node (internal error)");
		}
	}

	stmt->tableElts = columns;
	stmt->constraints = constraints;

/* Now run through the "deferred list" to complete the query transformation.
 * For PRIMARY KEY, mark each column as NOT NULL and create an index.
 * For UNIQUE, create an index as for PRIMARY KEY, but do not insist on
 * NOT NULL.
 */
	while (dlist != NIL)
	{
		constraint = lfirst(dlist);
		Assert(IsA(constraint, Constraint));
		Assert((constraint->contype == CONSTR_PRIMARY)
			   || (constraint->contype == CONSTR_UNIQUE));

		index = makeNode(IndexStmt);

		index->unique = TRUE;
		index->primary = (constraint->contype == CONSTR_PRIMARY ? TRUE : FALSE);
		if (index->primary)
		{
			if (pkey != NULL)
				elog(ERROR, "CREATE TABLE/PRIMARY KEY multiple primary keys"
					 " for table '%s' are not allowed", stmt->relname);
			pkey = index;
		}

		if (constraint->name != NULL)
			index->idxname = pstrdup(constraint->name);
		else if (constraint->contype == CONSTR_PRIMARY)
			index->idxname = makeObjectName(stmt->relname, NULL, "pkey");
		else
			index->idxname = NULL; /* will set it later */

		index->relname = stmt->relname;
		index->accessMethod = "btree";
		index->indexParams = NIL;
		index->withClause = NIL;
		index->whereClause = NULL;

		foreach (keys, constraint->keys)
		{
			bool	found = false;

			key = (Ident *) lfirst(keys);
			Assert(IsA(key, Ident));
			column = NULL;
			foreach(columns, stmt->tableElts)
			{
				column = lfirst(columns);
				Assert(IsA(column, ColumnDef));
				if (strcmp(column->colname, key->name) == 0)
				{
					found = true;
					break;
				}
			}
			if (found)
			{
				/* found column in the new table; force it to be NOT NULL */
				if (constraint->contype == CONSTR_PRIMARY)
					column->is_not_null = TRUE;
			}
			else
			{
				/* try inherited tables */
				List *inhRelnames = stmt->inhRelnames;
				List *inher;

				foreach (inher, inhRelnames)
				{
					Value *inh = lfirst(inher);
					Relation rel;
					int count;

					Assert(IsA(inh, String));
					rel = heap_openr(strVal(inh), AccessShareLock);
					if (rel->rd_rel->relkind != RELKIND_RELATION)
						elog(ERROR, "inherited table \"%s\" is not a relation",
							 strVal(inh));
					for (count = 0; count < rel->rd_att->natts; count++)
					{
						Form_pg_attribute inhattr = rel->rd_att->attrs[count];
						char *inhname = NameStr(inhattr->attname);

						if (strcmp(key->name, inhname) == 0)
						{
							found = true;
							/*
							 * If the column is inherited, we currently have
							 * no easy way to force it to be NOT NULL.
							 * Only way I can see to fix this would be to
							 * convert the inherited-column info to ColumnDef
							 * nodes before we reach this point, and then
							 * create the table from those nodes rather than
							 * referencing the parent tables later.  That
							 * would likely be cleaner, but too much work
							 * to contemplate right now.  Instead, raise an
							 * error if the inherited column won't be NOT NULL.
							 * (Would a NOTICE be more reasonable?)
							 */
							if (constraint->contype == CONSTR_PRIMARY &&
								! inhattr->attnotnull)
								elog(ERROR, "inherited attribute \"%s\" cannot be a PRIMARY KEY because it is not marked NOT NULL",
									 inhname);
							break;
						}
					}
					heap_close(rel, NoLock);
					if (found)
						break;
				}
			}

			if (!found)
				elog(ERROR, "CREATE TABLE: column \"%s\" named in key does not exist",
					 key->name);

			iparam = makeNode(IndexElem);
			iparam->name = pstrdup(key->name);
			iparam->args = NIL;
			iparam->class = NULL;
			index->indexParams = lappend(index->indexParams, iparam);
		}

		ilist = lappend(ilist, index);
		dlist = lnext(dlist);
	}

	/*
	 * Scan the index list and remove any redundant index specifications.
	 * This can happen if, for instance, the user writes SERIAL PRIMARY KEY
	 * or SERIAL UNIQUE.  A strict reading of SQL92 would suggest raising
	 * an error instead, but that strikes me as too anal-retentive.
	 * - tgl 2001-02-14
	 */
	dlist = ilist;
	ilist = NIL;
	if (pkey != NULL)
	{
		/* Make sure we keep the PKEY index in preference to others... */
		ilist = makeList1(pkey);
	}
	while (dlist != NIL)
	{
		index = lfirst(dlist);

		/* if it's pkey, it's already in ilist */
		if (index != pkey)
		{
			bool		keep = true;
			List	   *priorlist;

			foreach(priorlist, ilist)
			{
				IndexStmt  *priorindex = lfirst(priorlist);

				if (equal(index->indexParams, priorindex->indexParams))
				{
					/*
					 * If the prior index is as yet unnamed, and this one
					 * is named, then transfer the name to the prior index.
					 * This ensures that if we have named and unnamed
					 * constraints, we'll use (at least one of) the names
					 * for the index.
					 */
					if (priorindex->idxname == NULL)
						priorindex->idxname = index->idxname;
					keep = false;
					break;
				}
			}

			if (keep)
				ilist = lappend(ilist, index);
		}

		dlist = lnext(dlist);
	}

	/*
	 * Finally, select unique names for all not-previously-named indices,
	 * and display notice messages.
	 */
	dlist = ilist;
	while (dlist != NIL)
	{
		index = lfirst(dlist);

		if (index->idxname == NULL && index->indexParams != NIL)
		{
			iparam = lfirst(index->indexParams);
			index->idxname = CreateIndexName(stmt->relname, iparam->name,
											 "key", ilist);
		}
		if (index->idxname == NULL)		/* should not happen */
			elog(ERROR, "CREATE TABLE: failed to make implicit index name");

		elog(NOTICE, "CREATE TABLE/%s will create implicit index '%s' for table '%s'",
			 (index->primary ? "PRIMARY KEY" : "UNIQUE"),
			 index->idxname, stmt->relname);

		dlist = lnext(dlist);
	}

	q->utilityStmt = (Node *) stmt;
	extras_before = blist;
	extras_after = ilist;

	/*
	 * Now process the FOREIGN KEY constraints and add appropriate queries
	 * to the extras_after statements list.
	 */
	if (fkconstraints != NIL)
	{
		CreateTrigStmt *fk_trigger;
		List	   *fk_attr;
		List	   *pk_attr;
		Ident	   *id;

		elog(NOTICE, "CREATE TABLE will create implicit trigger(s) for FOREIGN KEY check(s)");

		foreach(fkclist, fkconstraints)
		{
			fkconstraint = (FkConstraint *) lfirst(fkclist);

			/*
			 * If the constraint has no name, set it to <unnamed>
			 *
			 */
			if (fkconstraint->constr_name == NULL)
				fkconstraint->constr_name = "<unnamed>";

			/* 
			 * Check to see if the attributes mentioned by the constraint
			 * actually exist on this table.
			 */
			if (fkconstraint->fk_attrs!=NIL) {
				int found=0;
				List *cols;
				List *fkattrs;
				Ident *fkattr = NULL;
				ColumnDef *col;
				foreach(fkattrs, fkconstraint->fk_attrs) {
					found=0;
					fkattr=lfirst(fkattrs);
					foreach(cols, stmt->tableElts) {
						col=lfirst(cols);
						if (strcmp(col->colname, fkattr->name)==0) {
							found=1;
							break;
						}
					}
					if (!found)
						break;
				}
				if (!found) { /* try inherited tables */
					List *inher;
					List *inhRelnames=stmt->inhRelnames;
					Relation rel;
					foreach (inher, inhRelnames) {
						Value *inh=lfirst(inher);
						int count;

						Assert(IsA(inh, String));
						rel=heap_openr(strVal(inh), AccessShareLock);
						if (rel->rd_rel->relkind != RELKIND_RELATION)
							elog(ERROR, "inherited table \"%s\" is not a relation",
								strVal(inh));
						for (count = 0; count < rel->rd_att->natts; count++) {
							char *name=NameStr(rel->rd_att->attrs[count]->attname);
							if (strcmp(fkattr->name, name) == 0) {
								found=1;
								break;
							}
						}
						heap_close(rel, NoLock);
						if (found)
							break;
					}
				}
				else {
					found=1;
				}
				if (!found)
					elog(ERROR, "columns referenced in foreign key constraint not found.");
			}

			/*
			 * If the attribute list for the referenced table was omitted,
			 * lookup for the definition of the primary key. If the
			 * referenced table is this table, use the definition we found
			 * above, rather than looking to the system tables.
			 *
			 */
			if (fkconstraint->fk_attrs != NIL && fkconstraint->pk_attrs == NIL)
			{
				if (strcmp(fkconstraint->pktable_name, stmt->relname) != 0)
					transformFkeyGetPrimaryKey(fkconstraint);
				else if (pkey != NULL)
				{
					List	   *pkey_attr = pkey->indexParams;
					List	   *attr;
					IndexElem  *ielem;
					Ident	   *pkattr;

					foreach(attr, pkey_attr)
					{
						ielem = lfirst(attr);
						pkattr = (Ident *) makeNode(Ident);
						pkattr->name = pstrdup(ielem->name);
						pkattr->indirection = NIL;
						pkattr->isRel = false;
						fkconstraint->pk_attrs = lappend(fkconstraint->pk_attrs, pkattr);
					}
				}
				else
				{
					elog(ERROR, "PRIMARY KEY for referenced table \"%s\" not found",
						 fkconstraint->pktable_name);
				}
			}
			else {
				if (strcmp(fkconstraint->pktable_name, stmt->relname)!=0)
					transformFkeyCheckAttrs(fkconstraint);
				else {
					/* Get a unique/pk constraint from above */
					List *index;
					int found=0;
					foreach(index, ilist)
					{
						IndexStmt *ind=lfirst(index);
						IndexElem *indparm;
						List *indparms;
						List *pkattrs;
						Ident *pkattr;
						if (ind->unique) {
							int count=0;
							foreach(indparms, ind->indexParams) {
								count++;
							}
							if (count!=length(fkconstraint->pk_attrs))
								found=0;
							else {
								foreach(pkattrs, fkconstraint->pk_attrs) {
									found=0;
									pkattr=lfirst(pkattrs);
									foreach(indparms, ind->indexParams) {
										indparm=lfirst(indparms);
										if (strcmp(indparm->name, pkattr->name)==0) {
											found=1;
											break;
										}
									}
									if (!found)
										break;
								}
							}
						}
						if (found)
							break;
					}
					if (!found)
						elog(ERROR, "UNIQUE constraint matching given keys for referenced table \"%s\" not found",
							 fkconstraint->pktable_name);
				}
			}
			/*
			 * Build a CREATE CONSTRAINT TRIGGER statement for the CHECK
			 * action.
			 *
			 */
			fk_trigger = (CreateTrigStmt *) makeNode(CreateTrigStmt);
			fk_trigger->trigname = fkconstraint->constr_name;
			fk_trigger->relname = stmt->relname;
			fk_trigger->funcname = "RI_FKey_check_ins";
			fk_trigger->before = false;
			fk_trigger->row = true;
			fk_trigger->actions[0] = 'i';
			fk_trigger->actions[1] = 'u';
			fk_trigger->actions[2] = '\0';
			fk_trigger->lang = NULL;
			fk_trigger->text = NULL;

			fk_trigger->attr = NIL;
			fk_trigger->when = NULL;
			fk_trigger->isconstraint = true;
			fk_trigger->deferrable = fkconstraint->deferrable;
			fk_trigger->initdeferred = fkconstraint->initdeferred;
			fk_trigger->constrrelname = fkconstraint->pktable_name;

			fk_trigger->args = NIL;
			fk_trigger->args = lappend(fk_trigger->args,
									   makeString(fkconstraint->constr_name));
			fk_trigger->args = lappend(fk_trigger->args,
									   makeString(stmt->relname));
			fk_trigger->args = lappend(fk_trigger->args,
									   makeString(fkconstraint->pktable_name));
			fk_trigger->args = lappend(fk_trigger->args,
									   makeString(fkconstraint->match_type));
			fk_attr = fkconstraint->fk_attrs;
			pk_attr = fkconstraint->pk_attrs;
			if (length(fk_attr) != length(pk_attr))
			{
				elog(NOTICE, "Illegal FOREIGN KEY definition REFERENCES \"%s\"",
					 fkconstraint->pktable_name);
				elog(ERROR, "number of key attributes in referenced table must be equal to foreign key");
			}
			while (fk_attr != NIL)
			{
				id = (Ident *) lfirst(fk_attr);
				fk_trigger->args = lappend(fk_trigger->args,
										   makeString(id->name));

				id = (Ident *) lfirst(pk_attr);
				fk_trigger->args = lappend(fk_trigger->args,
										   makeString(id->name));

				fk_attr = lnext(fk_attr);
				pk_attr = lnext(pk_attr);
			}

			extras_after = lappend(extras_after, (Node *) fk_trigger);

			/*
			 * Build a CREATE CONSTRAINT TRIGGER statement for the ON
			 * DELETE action fired on the PK table !!!
			 *
			 */
			fk_trigger = (CreateTrigStmt *) makeNode(CreateTrigStmt);
			fk_trigger->trigname = fkconstraint->constr_name;
			fk_trigger->relname = fkconstraint->pktable_name;
			fk_trigger->before = false;
			fk_trigger->row = true;
			fk_trigger->actions[0] = 'd';
			fk_trigger->actions[1] = '\0';
			fk_trigger->lang = NULL;
			fk_trigger->text = NULL;

			fk_trigger->attr = NIL;
			fk_trigger->when = NULL;
			fk_trigger->isconstraint = true;
			fk_trigger->deferrable = fkconstraint->deferrable;
			fk_trigger->initdeferred = fkconstraint->initdeferred;
			fk_trigger->constrrelname = stmt->relname;
			switch ((fkconstraint->actions & FKCONSTR_ON_DELETE_MASK)
					>> FKCONSTR_ON_DELETE_SHIFT)
			{
				case FKCONSTR_ON_KEY_NOACTION:
					fk_trigger->funcname = "RI_FKey_noaction_del";
					break;
				case FKCONSTR_ON_KEY_RESTRICT:
					fk_trigger->deferrable = false;
					fk_trigger->initdeferred = false;
					fk_trigger->funcname = "RI_FKey_restrict_del";
					break;
				case FKCONSTR_ON_KEY_CASCADE:
					fk_trigger->funcname = "RI_FKey_cascade_del";
					break;
				case FKCONSTR_ON_KEY_SETNULL:
					fk_trigger->funcname = "RI_FKey_setnull_del";
					break;
				case FKCONSTR_ON_KEY_SETDEFAULT:
					fk_trigger->funcname = "RI_FKey_setdefault_del";
					break;
				default:
					elog(ERROR, "Only one ON DELETE action can be specified for FOREIGN KEY constraint");
					break;
			}

			fk_trigger->args = NIL;
			fk_trigger->args = lappend(fk_trigger->args,
									   makeString(fkconstraint->constr_name));
			fk_trigger->args = lappend(fk_trigger->args,
									   makeString(stmt->relname));
			fk_trigger->args = lappend(fk_trigger->args,
									   makeString(fkconstraint->pktable_name));
			fk_trigger->args = lappend(fk_trigger->args,
									   makeString(fkconstraint->match_type));
			fk_attr = fkconstraint->fk_attrs;
			pk_attr = fkconstraint->pk_attrs;
			while (fk_attr != NIL)
			{
				id = (Ident *) lfirst(fk_attr);
				fk_trigger->args = lappend(fk_trigger->args,
										   makeString(id->name));

				id = (Ident *) lfirst(pk_attr);
				fk_trigger->args = lappend(fk_trigger->args,
										   makeString(id->name));

				fk_attr = lnext(fk_attr);
				pk_attr = lnext(pk_attr);
			}

			extras_after = lappend(extras_after, (Node *) fk_trigger);

			/*
			 * Build a CREATE CONSTRAINT TRIGGER statement for the ON
			 * UPDATE action fired on the PK table !!!
			 *
			 */
			fk_trigger = (CreateTrigStmt *) makeNode(CreateTrigStmt);
			fk_trigger->trigname = fkconstraint->constr_name;
			fk_trigger->relname = fkconstraint->pktable_name;
			fk_trigger->before = false;
			fk_trigger->row = true;
			fk_trigger->actions[0] = 'u';
			fk_trigger->actions[1] = '\0';
			fk_trigger->lang = NULL;
			fk_trigger->text = NULL;

			fk_trigger->attr = NIL;
			fk_trigger->when = NULL;
			fk_trigger->isconstraint = true;
			fk_trigger->deferrable = fkconstraint->deferrable;
			fk_trigger->initdeferred = fkconstraint->initdeferred;
			fk_trigger->constrrelname = stmt->relname;
			switch ((fkconstraint->actions & FKCONSTR_ON_UPDATE_MASK)
					>> FKCONSTR_ON_UPDATE_SHIFT)
			{
				case FKCONSTR_ON_KEY_NOACTION:
					fk_trigger->funcname = "RI_FKey_noaction_upd";
					break;
				case FKCONSTR_ON_KEY_RESTRICT:
					fk_trigger->deferrable = false;
					fk_trigger->initdeferred = false;
					fk_trigger->funcname = "RI_FKey_restrict_upd";
					break;
				case FKCONSTR_ON_KEY_CASCADE:
					fk_trigger->funcname = "RI_FKey_cascade_upd";
					break;
				case FKCONSTR_ON_KEY_SETNULL:
					fk_trigger->funcname = "RI_FKey_setnull_upd";
					break;
				case FKCONSTR_ON_KEY_SETDEFAULT:
					fk_trigger->funcname = "RI_FKey_setdefault_upd";
					break;
				default:
					elog(ERROR, "Only one ON UPDATE action can be specified for FOREIGN KEY constraint");
					break;
			}

			fk_trigger->args = NIL;
			fk_trigger->args = lappend(fk_trigger->args,
									   makeString(fkconstraint->constr_name));
			fk_trigger->args = lappend(fk_trigger->args,
									   makeString(stmt->relname));
			fk_trigger->args = lappend(fk_trigger->args,
									   makeString(fkconstraint->pktable_name));
			fk_trigger->args = lappend(fk_trigger->args,
									   makeString(fkconstraint->match_type));
			fk_attr = fkconstraint->fk_attrs;
			pk_attr = fkconstraint->pk_attrs;
			while (fk_attr != NIL)
			{
				id = (Ident *) lfirst(fk_attr);
				fk_trigger->args = lappend(fk_trigger->args,
										   makeString(id->name));

				id = (Ident *) lfirst(pk_attr);
				fk_trigger->args = lappend(fk_trigger->args,
										   makeString(id->name));

				fk_attr = lnext(fk_attr);
				pk_attr = lnext(pk_attr);
			}

			extras_after = lappend(extras_after, (Node *) fk_trigger);
		}
	}

	return q;
}	/* transformCreateStmt() */


/*
 * transformIndexStmt -
 *	  transforms the qualification of the index statement
 */
static Query *
transformIndexStmt(ParseState *pstate, IndexStmt *stmt)
{
	Query	   *qry;

	qry = makeNode(Query);
	qry->commandType = CMD_UTILITY;

	/* take care of the where clause */
	stmt->whereClause = transformWhereClause(pstate, stmt->whereClause);

	qry->hasSubLinks = pstate->p_hasSubLinks;

	stmt->rangetable = pstate->p_rtable;

	qry->utilityStmt = (Node *) stmt;

	return qry;
}

/*
 * transformExtendStmt -
 *	  transform the qualifications of the Extend Index Statement
 *
 */
static Query *
transformExtendStmt(ParseState *pstate, ExtendStmt *stmt)
{
	Query	   *qry;

	qry = makeNode(Query);
	qry->commandType = CMD_UTILITY;

	/* take care of the where clause */
	stmt->whereClause = transformWhereClause(pstate, stmt->whereClause);

	qry->hasSubLinks = pstate->p_hasSubLinks;

	stmt->rangetable = pstate->p_rtable;

	qry->utilityStmt = (Node *) stmt;
	return qry;
}

/*
 * transformRuleStmt -
 *	  transform a Create Rule Statement. The actions is a list of parse
 *	  trees which is transformed into a list of query trees.
 */
static Query *
transformRuleStmt(ParseState *pstate, RuleStmt *stmt)
{
	Query	   *qry;
	RangeTblEntry *oldrte;
	RangeTblEntry *newrte;

	qry = makeNode(Query);
	qry->commandType = CMD_UTILITY;
	qry->utilityStmt = (Node *) stmt;

	/*
	 * To avoid deadlock, make sure the first thing we do is grab
	 * AccessExclusiveLock on the target relation.  This will be
	 * needed by DefineQueryRewrite(), and we don't want to grab a lesser
	 * lock beforehand.  We don't need to hold a refcount on the relcache
	 * entry, however.
	 */
	heap_close(heap_openr(stmt->object->relname, AccessExclusiveLock),
			   NoLock);

	/*
	 * NOTE: 'OLD' must always have a varno equal to 1 and 'NEW'
	 * equal to 2.  Set up their RTEs in the main pstate for use
	 * in parsing the rule qualification.
	 */
	Assert(pstate->p_rtable == NIL);
	oldrte = addRangeTableEntry(pstate, stmt->object->relname,
								makeAttr("*OLD*", NULL),
								false, true);
	newrte = addRangeTableEntry(pstate, stmt->object->relname,
								makeAttr("*NEW*", NULL),
								false, true);
	/* Must override addRangeTableEntry's default access-check flags */
	oldrte->checkForRead = false;
	newrte->checkForRead = false;
	/*
	 * They must be in the namespace too for lookup purposes, but only add
	 * the one(s) that are relevant for the current kind of rule.  In an
	 * UPDATE rule, quals must refer to OLD.field or NEW.field to be
	 * unambiguous, but there's no need to be so picky for INSERT & DELETE.
	 * (Note we marked the RTEs "inFromCl = true" above to allow unqualified
	 * references to their fields.)  We do not add them to the joinlist.
	 */
	switch (stmt->event)
	{
		case CMD_SELECT:
			addRTEtoQuery(pstate, oldrte, false, true);
			break;
		case CMD_UPDATE:
			addRTEtoQuery(pstate, oldrte, false, true);
			addRTEtoQuery(pstate, newrte, false, true);
			break;
		case CMD_INSERT:
			addRTEtoQuery(pstate, newrte, false, true);
			break;
		case CMD_DELETE:
			addRTEtoQuery(pstate, oldrte, false, true);
			break;
		default:
			elog(ERROR, "transformRuleStmt: unexpected event type %d",
				 (int) stmt->event);
			break;
	}

	/* take care of the where clause */
	stmt->whereClause = transformWhereClause(pstate, stmt->whereClause);

	if (length(pstate->p_rtable) != 2) /* naughty, naughty... */
		elog(ERROR, "Rule WHERE condition may not contain references to other relations");

	/* save info about sublinks in where clause */
	qry->hasSubLinks = pstate->p_hasSubLinks;

	/*
	 * 'instead nothing' rules with a qualification need a query
	 * rangetable so the rewrite handler can add the negated rule
	 * qualification to the original query. We create a query with the new
	 * command type CMD_NOTHING here that is treated specially by the
	 * rewrite system.
	 */
	if (stmt->actions == NIL)
	{
		Query	   *nothing_qry = makeNode(Query);

		nothing_qry->commandType = CMD_NOTHING;
		nothing_qry->rtable = pstate->p_rtable;
		nothing_qry->jointree = makeFromExpr(NIL, NULL); /* no join wanted */

		stmt->actions = makeList1(nothing_qry);
	}
	else
	{
		List	   *actions;

		/*
		 * transform each statement, like parse_analyze()
		 */
		foreach(actions, stmt->actions)
		{
			ParseState *sub_pstate = make_parsestate(pstate->parentParseState);
			Query	   *sub_qry,
					   *top_subqry;
			bool		has_old,
						has_new;

			/*
			 * Set up OLD/NEW in the rtable for this statement.  The entries
			 * are marked not inFromCl because we don't want them to be
			 * referred to by unqualified field names nor "*" in the rule
			 * actions.  We must add them to the namespace, however, or they
			 * won't be accessible at all.  We decide later whether to put
			 * them in the joinlist.
			 */
			oldrte = addRangeTableEntry(sub_pstate, stmt->object->relname,
										makeAttr("*OLD*", NULL),
										false, false);
			newrte = addRangeTableEntry(sub_pstate, stmt->object->relname,
										makeAttr("*NEW*", NULL),
										false, false);
			oldrte->checkForRead = false;
			newrte->checkForRead = false;
			addRTEtoQuery(sub_pstate, oldrte, false, true);
			addRTEtoQuery(sub_pstate, newrte, false, true);

			/* Transform the rule action statement */
			top_subqry = transformStmt(sub_pstate, lfirst(actions));

			/*
			 * If the action is INSERT...SELECT, OLD/NEW have been pushed
			 * down into the SELECT, and that's what we need to look at.
			 * (Ugly kluge ... try to fix this when we redesign querytrees.)
			 */
			sub_qry = getInsertSelectQuery(top_subqry, NULL);

			/*
			 * Validate action's use of OLD/NEW, qual too
			 */
			has_old =
				rangeTableEntry_used((Node *) sub_qry, PRS2_OLD_VARNO, 0) ||
				rangeTableEntry_used(stmt->whereClause, PRS2_OLD_VARNO, 0);
			has_new =
				rangeTableEntry_used((Node *) sub_qry, PRS2_NEW_VARNO, 0) ||
				rangeTableEntry_used(stmt->whereClause, PRS2_NEW_VARNO, 0);

			switch (stmt->event)
			{
				case CMD_SELECT:
					if (has_old)
						elog(ERROR, "ON SELECT rule may not use OLD");
					if (has_new)
						elog(ERROR, "ON SELECT rule may not use NEW");
					break;
				case CMD_UPDATE:
					/* both are OK */
					break;
				case CMD_INSERT:
					if (has_old)
						elog(ERROR, "ON INSERT rule may not use OLD");
					break;
				case CMD_DELETE:
					if (has_new)
						elog(ERROR, "ON DELETE rule may not use NEW");
					break;
				default:
					elog(ERROR, "transformRuleStmt: unexpected event type %d",
						 (int) stmt->event);
					break;
			}

			/*
			 * For efficiency's sake, add OLD to the rule action's jointree
			 * only if it was actually referenced in the statement or qual.
			 *
			 * For INSERT, NEW is not really a relation (only a reference to
			 * the to-be-inserted tuple) and should never be added to the
			 * jointree.
			 *
			 * For UPDATE, we treat NEW as being another kind of reference to
			 * OLD, because it represents references to *transformed* tuples
			 * of the existing relation.  It would be wrong to enter NEW
			 * separately in the jointree, since that would cause a double
			 * join of the updated relation.  It's also wrong to fail to make
			 * a jointree entry if only NEW and not OLD is mentioned.
			 */
			if (has_old || (has_new && stmt->event == CMD_UPDATE))
			{
				/* hack so we can use addRTEtoQuery() */
				sub_pstate->p_rtable = sub_qry->rtable;
				sub_pstate->p_joinlist = sub_qry->jointree->fromlist;
				addRTEtoQuery(sub_pstate, oldrte, true, false);
				sub_qry->jointree->fromlist = sub_pstate->p_joinlist;
			}

			lfirst(actions) = top_subqry;

			release_pstate_resources(sub_pstate);
			pfree(sub_pstate);
		}
	}

	return qry;
}


/*
 * transformSelectStmt -
 *	  transforms a Select Statement
 *
 * Note: this is also used for DECLARE CURSOR statements.
 */
static Query *
transformSelectStmt(ParseState *pstate, SelectStmt *stmt)
{
	Query	   *qry = makeNode(Query);
	Node	   *qual;

	qry->commandType = CMD_SELECT;

	if (stmt->portalname)
	{
		/* DECLARE CURSOR */
		if (stmt->into)
			elog(ERROR, "DECLARE CURSOR must not specify INTO");
		if (stmt->forUpdate)
			elog(ERROR, "DECLARE/UPDATE is not supported"
				 "\n\tCursors must be READ ONLY");
		/*
		 *	15 august 1991 -- since 3.0 postgres does locking
		 *	right, we discovered that portals were violating
		 *	locking protocol.  portal locks cannot span xacts.
		 *	as a short-term fix, we installed the check here.
		 *							-- mao
		 */
		if (!IsTransactionBlock())
			elog(ERROR, "DECLARE CURSOR may only be used in begin/end transaction blocks");

		qry->into = stmt->portalname;
		qry->isTemp = stmt->istemp;
		qry->isPortal = TRUE;
		qry->isBinary = stmt->binary; /* internal portal */
	}
	else
	{
		/* SELECT */
		qry->into = stmt->into;
		qry->isTemp = stmt->istemp;
		qry->isPortal = FALSE;
		qry->isBinary = FALSE;
	}

	/* make FOR UPDATE clause available to addRangeTableEntry */
	pstate->p_forUpdate = stmt->forUpdate;

	/* process the FROM clause */
	transformFromClause(pstate, stmt->fromClause);

	/* transform targetlist and WHERE */
	qry->targetList = transformTargetList(pstate, stmt->targetList);

	qual = transformWhereClause(pstate, stmt->whereClause);

	/*
	 * Initial processing of HAVING clause is just like WHERE clause.
	 * Additional work will be done in optimizer/plan/planner.c.
	 */
	qry->havingQual = transformWhereClause(pstate, stmt->havingClause);

	qry->groupClause = transformGroupClause(pstate,
											stmt->groupClause,
											qry->targetList);

	qry->sortClause = transformSortClause(pstate,
										  stmt->sortClause,
										  qry->targetList);

	qry->distinctClause = transformDistinctClause(pstate,
												  stmt->distinctClause,
												  qry->targetList,
												  &qry->sortClause);

	qry->limitOffset = stmt->limitOffset;
	qry->limitCount = stmt->limitCount;

	qry->hasSubLinks = pstate->p_hasSubLinks;
	qry->hasAggs = pstate->p_hasAggs;
	if (pstate->p_hasAggs || qry->groupClause || qry->havingQual)
		parseCheckAggregates(pstate, qry, qual);

	qry->rtable = pstate->p_rtable;
	qry->jointree = makeFromExpr(pstate->p_joinlist, qual);

	if (stmt->forUpdate != NIL)
		transformForUpdate(qry, stmt->forUpdate);

	return qry;
}

/*
 * transformSetOperationsStmt -
 *	  transforms a set-operations tree
 *
 * A set-operation tree is just a SELECT, but with UNION/INTERSECT/EXCEPT
 * structure to it.  We must transform each leaf SELECT and build up a top-
 * level Query that contains the leaf SELECTs as subqueries in its rangetable.
 * The tree of set operations is converted into the setOperations field of
 * the top-level Query.
 */
static Query *
transformSetOperationStmt(ParseState *pstate, SelectStmt *stmt)
{
	Query	   *qry = makeNode(Query);
	SelectStmt *leftmostSelect;
	int			leftmostRTI;
	Query	   *leftmostQuery;
	SetOperationStmt *sostmt;
	char	   *into;
	bool		istemp;
	char	   *portalname;
	bool		binary;
	List	   *sortClause;
	Node	   *limitOffset;
	Node	   *limitCount;
	List	   *forUpdate;
	Node	   *node;
	List	   *lefttl,
			   *dtlist,
			   *targetvars,
			   *targetnames,
			   *sv_namespace;
	JoinExpr   *jnode;
	int			tllen;

	qry->commandType = CMD_SELECT;

	/*
	 * Find leftmost leaf SelectStmt; extract the one-time-only items
	 * from it and from the top-level node.
	 */
	leftmostSelect = stmt->larg;
	while (leftmostSelect && leftmostSelect->op != SETOP_NONE)
		leftmostSelect = leftmostSelect->larg;
	Assert(leftmostSelect && IsA(leftmostSelect, SelectStmt) &&
		   leftmostSelect->larg == NULL);
	into = leftmostSelect->into;
	istemp = leftmostSelect->istemp;
	portalname = stmt->portalname;
	binary = stmt->binary;

	/* clear them to prevent complaints in transformSetOperationTree() */
	leftmostSelect->into = NULL;
	leftmostSelect->istemp = false;
	stmt->portalname = NULL;
	stmt->binary = false;

	/*
	 * These are not one-time, exactly, but we want to process them here
	 * and not let transformSetOperationTree() see them --- else it'll just
	 * recurse right back here!
	 */
	sortClause = stmt->sortClause;
	limitOffset = stmt->limitOffset;
	limitCount = stmt->limitCount;
	forUpdate = stmt->forUpdate;

	stmt->sortClause = NIL;
	stmt->limitOffset = NULL;
	stmt->limitCount = NULL;
	stmt->forUpdate = NIL;

	/* We don't support forUpdate with set ops at the moment. */
	if (forUpdate)
		elog(ERROR, "SELECT FOR UPDATE is not allowed with UNION/INTERSECT/EXCEPT");

	/*
	 * Recursively transform the components of the tree.
	 */
	sostmt = (SetOperationStmt *) transformSetOperationTree(pstate, stmt);
	Assert(sostmt && IsA(sostmt, SetOperationStmt));
	qry->setOperations = (Node *) sostmt;

	/*
	 * Re-find leftmost SELECT (now it's a sub-query in rangetable)
	 */
	node = sostmt->larg;
	while (node && IsA(node, SetOperationStmt))
		node = ((SetOperationStmt *) node)->larg;
	Assert(node && IsA(node, RangeTblRef));
	leftmostRTI = ((RangeTblRef *) node)->rtindex;
	leftmostQuery = rt_fetch(leftmostRTI, pstate->p_rtable)->subquery;
	Assert(leftmostQuery != NULL);
	/*
	 * Generate dummy targetlist for outer query using column names of
	 * leftmost select and common datatypes of topmost set operation.
	 * Also make lists of the dummy vars and their names for use in
	 * parsing ORDER BY.
	 */
	qry->targetList = NIL;
	targetvars = NIL;
	targetnames = NIL;
	lefttl = leftmostQuery->targetList;
	foreach(dtlist, sostmt->colTypes)
	{
		Oid		colType = (Oid) lfirsti(dtlist);
		Resdom *leftResdom = ((TargetEntry *) lfirst(lefttl))->resdom;
		char   *colName = pstrdup(leftResdom->resname);
		Resdom *resdom;
		Node   *expr;

		resdom = makeResdom((AttrNumber) pstate->p_last_resno++,
							colType,
							-1,
							colName,
							false);
		expr = (Node *) makeVar(leftmostRTI,
								leftResdom->resno,
								colType,
								-1,
								0);
		qry->targetList = lappend(qry->targetList,
								  makeTargetEntry(resdom, expr));
		targetvars = lappend(targetvars, expr);
		targetnames = lappend(targetnames, makeString(colName));
		lefttl = lnext(lefttl);
	}
	/*
	 * Insert one-time items into top-level query
	 *
	 * This needs to agree with transformSelectStmt!
	 */
	if (portalname)
	{
		/* DECLARE CURSOR */
		if (into)
			elog(ERROR, "DECLARE CURSOR must not specify INTO");
		if (forUpdate)
			elog(ERROR, "DECLARE/UPDATE is not supported"
				 "\n\tCursors must be READ ONLY");
		/*
		 *	15 august 1991 -- since 3.0 postgres does locking
		 *	right, we discovered that portals were violating
		 *	locking protocol.  portal locks cannot span xacts.
		 *	as a short-term fix, we installed the check here.
		 *							-- mao
		 */
		if (!IsTransactionBlock())
			elog(ERROR, "DECLARE CURSOR may only be used in begin/end transaction blocks");

		qry->into = portalname;
		qry->isTemp = istemp;
		qry->isPortal = TRUE;
		qry->isBinary = binary; /* internal portal */
	}
	else
	{
		/* SELECT */
		qry->into = into;
		qry->isTemp = istemp;
		qry->isPortal = FALSE;
		qry->isBinary = FALSE;
	}

	/*
	 * As a first step towards supporting sort clauses that are expressions
	 * using the output columns, generate a namespace entry that makes the
	 * output columns visible.  A JoinExpr node is handy for this, since
	 * we can easily control the Vars generated upon matches.
	 *
	 * Note: we don't yet do anything useful with such cases, but at least
	 * "ORDER BY upper(foo)" will draw the right error message rather than
	 * "foo not found".
	 */
	jnode = makeNode(JoinExpr);
	jnode->colnames = targetnames;
	jnode->colvars = targetvars;

	sv_namespace = pstate->p_namespace;
	pstate->p_namespace = makeList1(jnode);

	/*
	 * For now, we don't support resjunk sort clauses on the output of a
	 * setOperation tree --- you can only use the SQL92-spec options of
	 * selecting an output column by name or number.  Enforce by checking
	 * that transformSortClause doesn't add any items to tlist.
	 */
	tllen = length(qry->targetList);

	qry->sortClause = transformSortClause(pstate,
										  sortClause,
										  qry->targetList);

	pstate->p_namespace = sv_namespace;

	if (tllen != length(qry->targetList))
		elog(ERROR, "ORDER BY on a UNION/INTERSECT/EXCEPT result must be on one of the result columns");

	qry->limitOffset = limitOffset;
	qry->limitCount = limitCount;

	qry->hasSubLinks = pstate->p_hasSubLinks;
	qry->hasAggs = pstate->p_hasAggs;
	if (pstate->p_hasAggs || qry->groupClause || qry->havingQual)
		parseCheckAggregates(pstate, qry, NULL);

	qry->rtable = pstate->p_rtable;
	qry->jointree = makeFromExpr(pstate->p_joinlist, NULL);

	if (forUpdate != NIL)
		transformForUpdate(qry, forUpdate);

	return qry;
}

/*
 * transformSetOperationTree
 *		Recursively transform leaves and internal nodes of a set-op tree
 */
static Node *
transformSetOperationTree(ParseState *pstate, SelectStmt *stmt)
{
	bool	isLeaf;

	Assert(stmt && IsA(stmt, SelectStmt));

	/*
	 * Validity-check both leaf and internal SELECTs for disallowed ops.
	 */
	if (stmt->into)
		elog(ERROR, "INTO is only allowed on first SELECT of UNION/INTERSECT/EXCEPT");
	if (stmt->portalname)		/* should not happen */
		elog(ERROR, "Portal may not appear in UNION/INTERSECT/EXCEPT");
	/* We don't support forUpdate with set ops at the moment. */
	if (stmt->forUpdate)
		elog(ERROR, "SELECT FOR UPDATE is not allowed with UNION/INTERSECT/EXCEPT");

	/*
	 * If an internal node of a set-op tree has ORDER BY, UPDATE, or LIMIT
	 * clauses attached, we need to treat it like a leaf node to generate
	 * an independent sub-Query tree.  Otherwise, it can be represented by
	 * a SetOperationStmt node underneath the parent Query.
	 */
	if (stmt->op == SETOP_NONE)
	{
		Assert(stmt->larg == NULL && stmt->rarg == NULL);
		isLeaf = true;
	}
	else
	{
		Assert(stmt->larg != NULL && stmt->rarg != NULL);
		if (stmt->sortClause || stmt->limitOffset || stmt->limitCount ||
			stmt->forUpdate)
			isLeaf = true;
		else
			isLeaf = false;
	}

	if (isLeaf)
	{
		/* Process leaf SELECT */
		List   *selectList;
		Query  *selectQuery;
		char	selectName[32];
		RangeTblEntry *rte;
		RangeTblRef *rtr;

		/*
		 * Transform SelectStmt into a Query.
		 *
		 * Note: previously transformed sub-queries don't affect the parsing
		 * of this sub-query, because they are not in the toplevel pstate's
		 * namespace list.
		 */
		selectList = parse_analyze((Node *) stmt, pstate);

		Assert(length(selectList) == 1);
		selectQuery = (Query *) lfirst(selectList);
		/*
		 * Make the leaf query be a subquery in the top-level rangetable.
		 */
		sprintf(selectName, "*SELECT* %d", length(pstate->p_rtable) + 1);
		rte = addRangeTableEntryForSubquery(pstate,
											selectQuery,
											makeAttr(pstrdup(selectName),
													 NULL),
											false);
		/*
		 * Return a RangeTblRef to replace the SelectStmt in the set-op tree.
		 */
		rtr = makeNode(RangeTblRef);
		/* assume new rte is at end */
		rtr->rtindex = length(pstate->p_rtable);
		Assert(rte == rt_fetch(rtr->rtindex, pstate->p_rtable));
		return (Node *) rtr;
	}
	else
	{
		/* Process an internal node (set operation node) */
		SetOperationStmt *op = makeNode(SetOperationStmt);
		List   *lcoltypes;
		List   *rcoltypes;
		const char *context;

		context = (stmt->op == SETOP_UNION ? "UNION" :
				   (stmt->op == SETOP_INTERSECT ? "INTERSECT" :
					"EXCEPT"));

		op->op = stmt->op;
		op->all = stmt->all;

		/*
		 * Recursively transform the child nodes.
		 */
		op->larg = transformSetOperationTree(pstate, stmt->larg);
		op->rarg = transformSetOperationTree(pstate, stmt->rarg);
		/*
		 * Verify that the two children have the same number of non-junk
		 * columns, and determine the types of the merged output columns.
		 */
		lcoltypes = getSetColTypes(pstate, op->larg);
		rcoltypes = getSetColTypes(pstate, op->rarg);
		if (length(lcoltypes) != length(rcoltypes))
			elog(ERROR, "Each %s query must have the same number of columns",
				 context);
		op->colTypes = NIL;
		while (lcoltypes != NIL)
		{
			Oid		lcoltype = (Oid) lfirsti(lcoltypes);
			Oid		rcoltype = (Oid) lfirsti(rcoltypes);
			Oid		rescoltype;

			rescoltype = select_common_type(makeListi2(lcoltype, rcoltype),
											context);
			op->colTypes = lappendi(op->colTypes, rescoltype);
			lcoltypes = lnext(lcoltypes);
			rcoltypes = lnext(rcoltypes);
		}

		return (Node *) op;
	}
}

/*
 * getSetColTypes
 *		Get output column types of an (already transformed) set-op node
 */
static List *
getSetColTypes(ParseState *pstate, Node *node)
{
	if (IsA(node, RangeTblRef))
	{
		RangeTblRef *rtr = (RangeTblRef *) node;
		RangeTblEntry *rte = rt_fetch(rtr->rtindex, pstate->p_rtable);
		Query  *selectQuery = rte->subquery;
		List   *result = NIL;
		List   *tl;

		Assert(selectQuery != NULL);
		/* Get types of non-junk columns */
		foreach(tl, selectQuery->targetList)
		{
			TargetEntry *tle = (TargetEntry *) lfirst(tl);
			Resdom	   *resnode = tle->resdom;

			if (resnode->resjunk)
				continue;
			result = lappendi(result, resnode->restype);
		}
		return result;
	}
	else if (IsA(node, SetOperationStmt))
	{
		SetOperationStmt *op = (SetOperationStmt *) node;

		/* Result already computed during transformation of node */
		Assert(op->colTypes != NIL);
		return op->colTypes;
	}
	else
	{
		elog(ERROR, "getSetColTypes: unexpected node %d",
			 (int) nodeTag(node));
		return NIL;				/* keep compiler quiet */
	}
}


/*
 * transformUpdateStmt -
 *	  transforms an update statement
 *
 */
static Query *
transformUpdateStmt(ParseState *pstate, UpdateStmt *stmt)
{
	Query	   *qry = makeNode(Query);
	Node	   *qual;
	List	   *origTargetList;
	List	   *tl;

	qry->commandType = CMD_UPDATE;
	pstate->p_is_update = true;

	qry->resultRelation = setTargetTable(pstate, stmt->relname,
										 interpretInhOption(stmt->inhOpt),
										 true);

	/*
	 * the FROM clause is non-standard SQL syntax. We used to be able to
	 * do this with REPLACE in POSTQUEL so we keep the feature.
	 */
	transformFromClause(pstate, stmt->fromClause);

	qry->targetList = transformTargetList(pstate, stmt->targetList);

	qual = transformWhereClause(pstate, stmt->whereClause);

	qry->rtable = pstate->p_rtable;
	qry->jointree = makeFromExpr(pstate->p_joinlist, qual);

	qry->hasSubLinks = pstate->p_hasSubLinks;
	qry->hasAggs = pstate->p_hasAggs;
	if (pstate->p_hasAggs)
		parseCheckAggregates(pstate, qry, qual);

	/*
	 * Now we are done with SELECT-like processing, and can get on with
	 * transforming the target list to match the UPDATE target columns.
	 */

	/* Prepare to assign non-conflicting resnos to resjunk attributes */
	if (pstate->p_last_resno <= pstate->p_target_relation->rd_rel->relnatts)
		pstate->p_last_resno = pstate->p_target_relation->rd_rel->relnatts + 1;

	/* Prepare non-junk columns for assignment to target table */
	origTargetList = stmt->targetList;
	foreach(tl, qry->targetList)
	{
		TargetEntry *tle = (TargetEntry *) lfirst(tl);
		Resdom	   *resnode = tle->resdom;
		ResTarget  *origTarget;

		if (resnode->resjunk)
		{

			/*
			 * Resjunk nodes need no additional processing, but be sure
			 * they have names and resnos that do not match any target
			 * columns; else rewriter or planner might get confused.
			 */
			resnode->resname = "?resjunk?";
			resnode->resno = (AttrNumber) pstate->p_last_resno++;
			continue;
		}
		if (origTargetList == NIL)
			elog(ERROR, "UPDATE target count mismatch --- internal error");
		origTarget = (ResTarget *) lfirst(origTargetList);
		updateTargetListEntry(pstate, tle, origTarget->name,
							  attnameAttNum(pstate->p_target_relation,
											origTarget->name),
							  origTarget->indirection);
		origTargetList = lnext(origTargetList);
	}
	if (origTargetList != NIL)
		elog(ERROR, "UPDATE target count mismatch --- internal error");

	return qry;
}

/*
 * tranformAlterTableStmt -
 *	transform an Alter Table Statement
 *
 */
static Query *
transformAlterTableStmt(ParseState *pstate, AlterTableStmt *stmt)
{
	Query	   *qry;

	qry = makeNode(Query);
	qry->commandType = CMD_UTILITY;

	/*
	 * The only subtypes that currently have special handling are 'A'dd
	 * column and Add 'C'onstraint.  In addition, right now only Foreign
	 * Key 'C'onstraints have a special transformation.
	 *
	 */
	switch (stmt->subtype)
	{
		case 'A':
			transformColumnType(pstate, (ColumnDef *) stmt->def);
			break;
		case 'C':
			if (stmt->def && IsA(stmt->def, FkConstraint))
			{
				CreateTrigStmt *fk_trigger;
				List	   *fk_attr;
				List	   *pk_attr;
				Ident	   *id;
				FkConstraint *fkconstraint;

				extras_after = NIL;
				elog(NOTICE, "ALTER TABLE ... ADD CONSTRAINT will create implicit trigger(s) for FOREIGN KEY check(s)");

				fkconstraint = (FkConstraint *) stmt->def;

				/*
				 * If the constraint has no name, set it to <unnamed>
				 *
				 */
				if (fkconstraint->constr_name == NULL)
					fkconstraint->constr_name = "<unnamed>";

				/*
				 * If the attribute list for the referenced table was
				 * omitted, lookup for the definition of the primary key
				 *
				 */
				if (fkconstraint->fk_attrs != NIL && fkconstraint->pk_attrs == NIL)
					transformFkeyGetPrimaryKey(fkconstraint);

				/*
				 * Build a CREATE CONSTRAINT TRIGGER statement for the
				 * CHECK action.
				 *
				 */
				fk_trigger = (CreateTrigStmt *) makeNode(CreateTrigStmt);
				fk_trigger->trigname = fkconstraint->constr_name;
				fk_trigger->relname = stmt->relname;
				fk_trigger->funcname = "RI_FKey_check_ins";
				fk_trigger->before = false;
				fk_trigger->row = true;
				fk_trigger->actions[0] = 'i';
				fk_trigger->actions[1] = 'u';
				fk_trigger->actions[2] = '\0';
				fk_trigger->lang = NULL;
				fk_trigger->text = NULL;

				fk_trigger->attr = NIL;
				fk_trigger->when = NULL;
				fk_trigger->isconstraint = true;
				fk_trigger->deferrable = fkconstraint->deferrable;
				fk_trigger->initdeferred = fkconstraint->initdeferred;
				fk_trigger->constrrelname = fkconstraint->pktable_name;

				fk_trigger->args = NIL;
				fk_trigger->args = lappend(fk_trigger->args,
										   makeString(fkconstraint->constr_name));
				fk_trigger->args = lappend(fk_trigger->args,
										   makeString(stmt->relname));
				fk_trigger->args = lappend(fk_trigger->args,
										   makeString(fkconstraint->pktable_name));
				fk_trigger->args = lappend(fk_trigger->args,
										   makeString(fkconstraint->match_type));
				fk_attr = fkconstraint->fk_attrs;
				pk_attr = fkconstraint->pk_attrs;
				if (length(fk_attr) != length(pk_attr))
				{
					elog(NOTICE, "Illegal FOREIGN KEY definition REFERENCES \"%s\"",
						 fkconstraint->pktable_name);
					elog(ERROR, "number of key attributes in referenced table must be equal to foreign key");
				}
				while (fk_attr != NIL)
				{
					id = (Ident *) lfirst(fk_attr);
					fk_trigger->args = lappend(fk_trigger->args,
											   makeString(id->name));

					id = (Ident *) lfirst(pk_attr);
					fk_trigger->args = lappend(fk_trigger->args,
											   makeString(id->name));

					fk_attr = lnext(fk_attr);
					pk_attr = lnext(pk_attr);
				}

				extras_after = lappend(extras_after, (Node *) fk_trigger);

				/*
				 * Build a CREATE CONSTRAINT TRIGGER statement for the ON
				 * DELETE action fired on the PK table !!!
				 *
				 */
				fk_trigger = (CreateTrigStmt *) makeNode(CreateTrigStmt);
				fk_trigger->trigname = fkconstraint->constr_name;
				fk_trigger->relname = fkconstraint->pktable_name;
				switch ((fkconstraint->actions & FKCONSTR_ON_DELETE_MASK)
						>> FKCONSTR_ON_DELETE_SHIFT)
				{
					case FKCONSTR_ON_KEY_NOACTION:
						fk_trigger->funcname = "RI_FKey_noaction_del";
						break;
					case FKCONSTR_ON_KEY_RESTRICT:
						fk_trigger->funcname = "RI_FKey_restrict_del";
						break;
					case FKCONSTR_ON_KEY_CASCADE:
						fk_trigger->funcname = "RI_FKey_cascade_del";
						break;
					case FKCONSTR_ON_KEY_SETNULL:
						fk_trigger->funcname = "RI_FKey_setnull_del";
						break;
					case FKCONSTR_ON_KEY_SETDEFAULT:
						fk_trigger->funcname = "RI_FKey_setdefault_del";
						break;
					default:
						elog(ERROR, "Only one ON DELETE action can be specified for FOREIGN KEY constraint");
						break;
				}
				fk_trigger->before = false;
				fk_trigger->row = true;
				fk_trigger->actions[0] = 'd';
				fk_trigger->actions[1] = '\0';
				fk_trigger->lang = NULL;
				fk_trigger->text = NULL;

				fk_trigger->attr = NIL;
				fk_trigger->when = NULL;
				fk_trigger->isconstraint = true;
				fk_trigger->deferrable = fkconstraint->deferrable;
				fk_trigger->initdeferred = fkconstraint->initdeferred;
				fk_trigger->constrrelname = stmt->relname;

				fk_trigger->args = NIL;
				fk_trigger->args = lappend(fk_trigger->args,
										   makeString(fkconstraint->constr_name));
				fk_trigger->args = lappend(fk_trigger->args,
										   makeString(stmt->relname));
				fk_trigger->args = lappend(fk_trigger->args,
										   makeString(fkconstraint->pktable_name));
				fk_trigger->args = lappend(fk_trigger->args,
										   makeString(fkconstraint->match_type));
				fk_attr = fkconstraint->fk_attrs;
				pk_attr = fkconstraint->pk_attrs;
				while (fk_attr != NIL)
				{
					id = (Ident *) lfirst(fk_attr);
					fk_trigger->args = lappend(fk_trigger->args,
											   makeString(id->name));

					id = (Ident *) lfirst(pk_attr);
					fk_trigger->args = lappend(fk_trigger->args,
											   makeString(id->name));

					fk_attr = lnext(fk_attr);
					pk_attr = lnext(pk_attr);
				}

				extras_after = lappend(extras_after, (Node *) fk_trigger);

				/*
				 * Build a CREATE CONSTRAINT TRIGGER statement for the ON
				 * UPDATE action fired on the PK table !!!
				 *
				 */
				fk_trigger = (CreateTrigStmt *) makeNode(CreateTrigStmt);
				fk_trigger->trigname = fkconstraint->constr_name;
				fk_trigger->relname = fkconstraint->pktable_name;
				switch ((fkconstraint->actions & FKCONSTR_ON_UPDATE_MASK)
						>> FKCONSTR_ON_UPDATE_SHIFT)
				{
					case FKCONSTR_ON_KEY_NOACTION:
						fk_trigger->funcname = "RI_FKey_noaction_upd";
						break;
					case FKCONSTR_ON_KEY_RESTRICT:
						fk_trigger->funcname = "RI_FKey_restrict_upd";
						break;
					case FKCONSTR_ON_KEY_CASCADE:
						fk_trigger->funcname = "RI_FKey_cascade_upd";
						break;
					case FKCONSTR_ON_KEY_SETNULL:
						fk_trigger->funcname = "RI_FKey_setnull_upd";
						break;
					case FKCONSTR_ON_KEY_SETDEFAULT:
						fk_trigger->funcname = "RI_FKey_setdefault_upd";
						break;
					default:
						elog(ERROR, "Only one ON UPDATE action can be specified for FOREIGN KEY constraint");
						break;
				}
				fk_trigger->before = false;
				fk_trigger->row = true;
				fk_trigger->actions[0] = 'u';
				fk_trigger->actions[1] = '\0';
				fk_trigger->lang = NULL;
				fk_trigger->text = NULL;

				fk_trigger->attr = NIL;
				fk_trigger->when = NULL;
				fk_trigger->isconstraint = true;
				fk_trigger->deferrable = fkconstraint->deferrable;
				fk_trigger->initdeferred = fkconstraint->initdeferred;
				fk_trigger->constrrelname = stmt->relname;

				fk_trigger->args = NIL;
				fk_trigger->args = lappend(fk_trigger->args,
										   makeString(fkconstraint->constr_name));
				fk_trigger->args = lappend(fk_trigger->args,
										   makeString(stmt->relname));
				fk_trigger->args = lappend(fk_trigger->args,
										   makeString(fkconstraint->pktable_name));
				fk_trigger->args = lappend(fk_trigger->args,
										   makeString(fkconstraint->match_type));
				fk_attr = fkconstraint->fk_attrs;
				pk_attr = fkconstraint->pk_attrs;
				while (fk_attr != NIL)
				{
					id = (Ident *) lfirst(fk_attr);
					fk_trigger->args = lappend(fk_trigger->args,
											   makeString(id->name));

					id = (Ident *) lfirst(pk_attr);
					fk_trigger->args = lappend(fk_trigger->args,
											   makeString(id->name));

					fk_attr = lnext(fk_attr);
					pk_attr = lnext(pk_attr);
				}

				extras_after = lappend(extras_after, (Node *) fk_trigger);
			}
			break;
		default:
			break;
	}
	qry->utilityStmt = (Node *) stmt;
	return qry;
}

/* exported so planner can check again after rewriting, query pullup, etc */
void
CheckSelectForUpdate(Query *qry)
{
	if (qry->setOperations)
		elog(ERROR, "SELECT FOR UPDATE is not allowed with UNION/INTERSECT/EXCEPT");
	if (qry->distinctClause != NIL)
		elog(ERROR, "SELECT FOR UPDATE is not allowed with DISTINCT clause");
	if (qry->groupClause != NIL)
		elog(ERROR, "SELECT FOR UPDATE is not allowed with GROUP BY clause");
	if (qry->hasAggs)
		elog(ERROR, "SELECT FOR UPDATE is not allowed with AGGREGATE");
}

static void
transformForUpdate(Query *qry, List *forUpdate)
{
	List	   *rowMarks = qry->rowMarks;
	List	   *l;
	List	   *rt;
	Index		i;

	CheckSelectForUpdate(qry);

	if (lfirst(forUpdate) == NULL)
	{
		/* all tables used in query */
		i = 0;
		foreach(rt, qry->rtable)
		{
			RangeTblEntry *rte = (RangeTblEntry *) lfirst(rt);

			++i;
			if (rte->subquery)
			{
				/* FOR UPDATE of subquery is propagated to subquery's rels */
				transformForUpdate(rte->subquery, makeList1(NULL));
			}
			else
			{
				if (!intMember(i, rowMarks)) /* avoid duplicates */
					rowMarks = lappendi(rowMarks, i);
				rte->checkForWrite = true;
			}
		}
	}
	else
	{
		/* just the named tables */
		foreach(l, forUpdate)
		{
			char	   *relname = lfirst(l);

			i = 0;
			foreach(rt, qry->rtable)
			{
				RangeTblEntry *rte = (RangeTblEntry *) lfirst(rt);

				++i;
				if (strcmp(rte->eref->relname, relname) == 0)
				{
					if (rte->subquery)
					{
						/* propagate to subquery */
						transformForUpdate(rte->subquery, makeList1(NULL));
					}
					else
					{
						if (!intMember(i, rowMarks)) /* avoid duplicates */
							rowMarks = lappendi(rowMarks, i);
						rte->checkForWrite = true;
					}
					break;
				}
			}
			if (rt == NIL)
				elog(ERROR, "FOR UPDATE: relation \"%s\" not found in FROM clause",
					 relname);
		}
	}

	qry->rowMarks = rowMarks;
}


/*
 * transformFkeyCheckAttrs -
 *
 *	Try to make sure that the attributes of a referenced table
 *      belong to a unique (or primary key) constraint.
 *
 */
static void 
transformFkeyCheckAttrs(FkConstraint *fkconstraint)
{
	Relation	pkrel;
	Form_pg_attribute *pkrel_attrs;
	List	   *indexoidlist,
			   *indexoidscan;
	int			i;
	bool		found = false;

	/* ----------
	 * Open the referenced table and get the attributes list
	 * ----------
	 */
	pkrel = heap_openr(fkconstraint->pktable_name, AccessShareLock);
	if (pkrel == NULL)
		elog(ERROR, "referenced table \"%s\" not found",
			 fkconstraint->pktable_name);
	pkrel_attrs = pkrel->rd_att->attrs;

	/* ----------
	 * Get the list of index OIDs for the table from the relcache,
	 * and look up each one in the pg_index syscache for each unique
	 * one, and then compare the attributes we were given to those
	 * defined.
	 * ----------
	 */
	indexoidlist = RelationGetIndexList(pkrel);

	foreach(indexoidscan, indexoidlist)
	{
		Oid		indexoid = lfirsti(indexoidscan);
		HeapTuple	indexTuple;
		Form_pg_index indexStruct;

		indexTuple = SearchSysCache(INDEXRELID,
									ObjectIdGetDatum(indexoid),
									0, 0, 0);
		if (!HeapTupleIsValid(indexTuple))
			elog(ERROR, "transformFkeyGetPrimaryKey: index %u not found",
				 indexoid);
		indexStruct = (Form_pg_index) GETSTRUCT(indexTuple);

		if (indexStruct->indisunique)
		{
			List *attrl;

			for (i = 0; i < INDEX_MAX_KEYS && indexStruct->indkey[i] != 0; i++);
			if (i!=length(fkconstraint->pk_attrs))
				found=false;
			else {
				/* go through the fkconstraint->pk_attrs list */
				foreach(attrl, fkconstraint->pk_attrs)
				{
					Ident *attr=lfirst(attrl);
					found = false;
					for (i = 0; i < INDEX_MAX_KEYS && indexStruct->indkey[i] != 0; i++)
					{
						int		pkattno = indexStruct->indkey[i];
						if (pkattno>0)
						{
							char *name = NameStr(pkrel_attrs[pkattno - 1]->attname);
							if (strcmp(name, attr->name)==0)
							{
								found = true;
								break;
							}
						}
					}
					if (!found)
						break;
				}
			}
		}
		ReleaseSysCache(indexTuple);
		if (found)
			break;		
	}
	if (!found)
		elog(ERROR, "UNIQUE constraint matching given keys for referenced table \"%s\" not found",
			 fkconstraint->pktable_name);

	freeList(indexoidlist);
	heap_close(pkrel, AccessShareLock);
}


/*
 * transformFkeyGetPrimaryKey -
 *
 *	Try to find the primary key attributes of a referenced table if
 *	the column list in the REFERENCES specification was omitted.
 *
 */
static void
transformFkeyGetPrimaryKey(FkConstraint *fkconstraint)
{
	Relation	pkrel;
	Form_pg_attribute *pkrel_attrs;
	List	   *indexoidlist,
			   *indexoidscan;
	HeapTuple	indexTuple = NULL;
	Form_pg_index indexStruct = NULL;
	int			i;

	/* ----------
	 * Open the referenced table and get the attributes list
	 * ----------
	 */
	pkrel = heap_openr(fkconstraint->pktable_name, AccessShareLock);
	if (pkrel == NULL)
		elog(ERROR, "referenced table \"%s\" not found",
			 fkconstraint->pktable_name);
	pkrel_attrs = pkrel->rd_att->attrs;

	/* ----------
	 * Get the list of index OIDs for the table from the relcache,
	 * and look up each one in the pg_index syscache until we find one
	 * marked primary key (hopefully there isn't more than one such).
	 * ----------
	 */
	indexoidlist = RelationGetIndexList(pkrel);

	foreach(indexoidscan, indexoidlist)
	{
		Oid		indexoid = lfirsti(indexoidscan);

		indexTuple = SearchSysCache(INDEXRELID,
									ObjectIdGetDatum(indexoid),
									0, 0, 0);
		if (!HeapTupleIsValid(indexTuple))
			elog(ERROR, "transformFkeyGetPrimaryKey: index %u not found",
				 indexoid);
		indexStruct = (Form_pg_index) GETSTRUCT(indexTuple);
		if (indexStruct->indisprimary)
			break;
		ReleaseSysCache(indexTuple);
		indexStruct = NULL;
	}

	freeList(indexoidlist);

	/* ----------
	 * Check that we found it
	 * ----------
	 */
	if (indexStruct == NULL)
		elog(ERROR, "PRIMARY KEY for referenced table \"%s\" not found",
			 fkconstraint->pktable_name);

	/* ----------
	 * Now build the list of PK attributes from the indkey definition
	 * using the attribute names of the PK relation descriptor
	 * ----------
	 */
	for (i = 0; i < INDEX_MAX_KEYS && indexStruct->indkey[i] != 0; i++)
	{
		int			pkattno = indexStruct->indkey[i];
		Ident	   *pkattr = makeNode(Ident);

		pkattr->name = DatumGetCString(DirectFunctionCall1(nameout,
						NameGetDatum(&(pkrel_attrs[pkattno - 1]->attname))));
		pkattr->indirection = NIL;
		pkattr->isRel = false;

		fkconstraint->pk_attrs = lappend(fkconstraint->pk_attrs, pkattr);
	}

	ReleaseSysCache(indexTuple);

	heap_close(pkrel, AccessShareLock);
}

/*
 * Preprocess a list of column constraint clauses
 * to attach constraint attributes to their primary constraint nodes
 * and detect inconsistent/misplaced constraint attributes.
 *
 * NOTE: currently, attributes are only supported for FOREIGN KEY primary
 * constraints, but someday they ought to be supported for other constraints.
 */
static void
transformConstraintAttrs(List *constraintList)
{
	Node	   *lastprimarynode = NULL;
	bool		saw_deferrability = false;
	bool		saw_initially = false;
	List	   *clist;

	foreach(clist, constraintList)
	{
		Node	   *node = lfirst(clist);

		if (!IsA(node, Constraint))
		{
			lastprimarynode = node;
			/* reset flags for new primary node */
			saw_deferrability = false;
			saw_initially = false;
		}
		else
		{
			Constraint *con = (Constraint *) node;

			switch (con->contype)
			{
				case CONSTR_ATTR_DEFERRABLE:
					if (lastprimarynode == NULL ||
						!IsA(lastprimarynode, FkConstraint))
						elog(ERROR, "Misplaced DEFERRABLE clause");
					if (saw_deferrability)
						elog(ERROR, "Multiple DEFERRABLE/NOT DEFERRABLE clauses not allowed");
					saw_deferrability = true;
					((FkConstraint *) lastprimarynode)->deferrable = true;
					break;
				case CONSTR_ATTR_NOT_DEFERRABLE:
					if (lastprimarynode == NULL ||
						!IsA(lastprimarynode, FkConstraint))
						elog(ERROR, "Misplaced NOT DEFERRABLE clause");
					if (saw_deferrability)
						elog(ERROR, "Multiple DEFERRABLE/NOT DEFERRABLE clauses not allowed");
					saw_deferrability = true;
					((FkConstraint *) lastprimarynode)->deferrable = false;
					if (saw_initially &&
						((FkConstraint *) lastprimarynode)->initdeferred)
						elog(ERROR, "INITIALLY DEFERRED constraint must be DEFERRABLE");
					break;
				case CONSTR_ATTR_DEFERRED:
					if (lastprimarynode == NULL ||
						!IsA(lastprimarynode, FkConstraint))
						elog(ERROR, "Misplaced INITIALLY DEFERRED clause");
					if (saw_initially)
						elog(ERROR, "Multiple INITIALLY IMMEDIATE/DEFERRED clauses not allowed");
					saw_initially = true;
					((FkConstraint *) lastprimarynode)->initdeferred = true;

					/*
					 * If only INITIALLY DEFERRED appears, assume
					 * DEFERRABLE
					 */
					if (!saw_deferrability)
						((FkConstraint *) lastprimarynode)->deferrable = true;
					else if (!((FkConstraint *) lastprimarynode)->deferrable)
						elog(ERROR, "INITIALLY DEFERRED constraint must be DEFERRABLE");
					break;
				case CONSTR_ATTR_IMMEDIATE:
					if (lastprimarynode == NULL ||
						!IsA(lastprimarynode, FkConstraint))
						elog(ERROR, "Misplaced INITIALLY IMMEDIATE clause");
					if (saw_initially)
						elog(ERROR, "Multiple INITIALLY IMMEDIATE/DEFERRED clauses not allowed");
					saw_initially = true;
					((FkConstraint *) lastprimarynode)->initdeferred = false;
					break;
				default:
					/* Otherwise it's not an attribute */
					lastprimarynode = node;
					/* reset flags for new primary node */
					saw_deferrability = false;
					saw_initially = false;
					break;
			}
		}
	}
}

/* Build a FromExpr node */
static FromExpr *
makeFromExpr(List *fromlist, Node *quals)
{
	FromExpr *f = makeNode(FromExpr);

	f->fromlist = fromlist;
	f->quals = quals;
	return f;
}

/*
 * Special handling of type definition for a column
 */
static void
transformColumnType(ParseState *pstate, ColumnDef *column)
{
	TypeName   *typename = column->typename;
	Type		ctype = typenameType(typename->name);

	/*
	 * If the column doesn't have an explicitly specified typmod, check to
	 * see if we want to insert a default length.
	 *
	 * Note that we deliberately do NOT look at array or set information
	 * here; "numeric[]" needs the same default typmod as "numeric".
	 */
	if (typename->typmod == -1)
	{
		switch (typeTypeId(ctype))
		{
			case BPCHAROID:
				/* "char" -> "char(1)" */
				typename->typmod = VARHDRSZ + 1;
				break;
			case NUMERICOID:
				typename->typmod = VARHDRSZ +
					((NUMERIC_DEFAULT_PRECISION << 16) | NUMERIC_DEFAULT_SCALE);
				break;
			case ZPBITOID:
				/* 'bit' -> 'bit(1)' */
				typename->typmod = 1;
				break;
		}
	}

	/*
	 * Is this the name of a complex type? If so, implement
	 * it as a set.
	 *
	 * XXX this is a hangover from ancient Berkeley code that probably
	 * doesn't work anymore anyway.
	 */
	 if (typeTypeRelid(ctype) != InvalidOid)
	 {
		 /* (Eventually add in here that the set can only
		  * contain one element.)
		  */
		 typename->setof = true;
	 }

	 ReleaseSysCache(ctype);
}
