Remove obsolete pg_constraint.consrc column

This has been deprecated and effectively unused for a long time.
Reviewed-by: Daniel Gustafsson <daniel@yesql.se>

doc/src/sgml/catalogs.sgml

@@ -2400,14 +2400,10 @@ SCRAM-SHA-256$<replaceable>&lt;iteration count&gt;</replaceable>:<replaceable>&l
       <entry><structfield>conbin</structfield></entry>
       <entry><type>pg_node_tree</type></entry>
       <entry></entry>
-      <entry>If a check constraint, an internal representation of the expression</entry>
-     </row>
-
-     <row>
-      <entry><structfield>consrc</structfield></entry>
-      <entry><type>text</type></entry>
-      <entry></entry>
-      <entry>If a check constraint, a human-readable representation of the expression</entry>
+      <entry>If a check constraint, an internal representation of the
+      expression.  (It's recommended to use
+      <function>pg_get_constraintdef()</function> to extract the definition of
+      a check constraint.)</entry>
      </row>
     </tbody>
    </tgroup>
@@ -2423,15 +2419,6 @@ SCRAM-SHA-256$<replaceable>&lt;iteration count&gt;</replaceable>:<replaceable>&l
    index.)
   </para>
 
-  <note>
-   <para>
-    <structfield>consrc</structfield> is not updated when referenced objects
-    change; for example, it won't track renaming of columns.  Rather than
-    relying on this field, it's best to use <function>pg_get_constraintdef()</function>
-    to extract the definition of a check constraint.
-   </para>
-  </note>
-
   <note>
    <para>
     <literal>pg_class.relchecks</literal> needs to agree with the

src/backend/catalog/heap.c

@@ -2315,7 +2315,6 @@ StoreRelCheck(Relation rel, const char *ccname, Node *expr,
 			  bool is_no_inherit, bool is_internal)
 {
 	char	   *ccbin;
-	char	   *ccsrc;
 	List	   *varList;
 	int			keycount;
 	int16	   *attNos;
@@ -2326,14 +2325,6 @@ StoreRelCheck(Relation rel, const char *ccname, Node *expr,
 	 */
 	ccbin = nodeToString(expr);
 
-	/*
-	 * Also deparse it to form the mostly-obsolete consrc field.
-	 */
-	ccsrc = deparse_expression(expr,
-							   deparse_context_for(RelationGetRelationName(rel),
-												   RelationGetRelid(rel)),
-							   false, false);
-
 	/*
 	 * Find columns of rel that are used in expr
 	 *
@@ -2406,14 +2397,12 @@ StoreRelCheck(Relation rel, const char *ccname, Node *expr,
 							  NULL, /* not an exclusion constraint */
 							  expr, /* Tree form of check constraint */
 							  ccbin,	/* Binary form of check constraint */
-							  ccsrc,	/* Source form of check constraint */
 							  is_local, /* conislocal */
 							  inhcount, /* coninhcount */
 							  is_no_inherit,	/* connoinherit */
 							  is_internal); /* internally constructed? */
 
 	pfree(ccbin);
-	pfree(ccsrc);
 
 	return constrOid;
 }

src/backend/catalog/index.c

@@ -1336,7 +1336,6 @@ index_constraint_create(Relation heapRelation,
 								   indexInfo->ii_ExclusionOps,
 								   NULL,	/* no check constraint */
 								   NULL,
-								   NULL,
 								   islocal,
 								   inhcount,
 								   noinherit,

src/backend/catalog/pg_constraint.c

@@ -78,7 +78,6 @@ CreateConstraintEntry(const char *constraintName,
 					  const Oid *exclOp,
 					  Node *conExpr,
 					  const char *conBin,
-					  const char *conSrc,
 					  bool conIsLocal,
 					  int conInhCount,
 					  bool conNoInherit,
@@ -218,22 +217,11 @@ CreateConstraintEntry(const char *constraintName,
 	else
 		nulls[Anum_pg_constraint_conexclop - 1] = true;
 
-	/*
-	 * initialize the binary form of the check constraint.
-	 */
 	if (conBin)
 		values[Anum_pg_constraint_conbin - 1] = CStringGetTextDatum(conBin);
 	else
 		nulls[Anum_pg_constraint_conbin - 1] = true;
 
-	/*
-	 * initialize the text form of the check constraint
-	 */
-	if (conSrc)
-		values[Anum_pg_constraint_consrc - 1] = CStringGetTextDatum(conSrc);
-	else
-		nulls[Anum_pg_constraint_consrc - 1] = true;
-
 	tup = heap_form_tuple(RelationGetDescr(conDesc), values, nulls);
 
 	conOid = CatalogTupleInsert(conDesc, tup);
@@ -703,7 +691,6 @@ clone_fk_constraints(Relation pg_constraint, Relation parentRel,
 								  NULL,
 								  NULL,
 								  NULL,
-								  NULL,
 								  false,
 								  1, false, true);
 		subclone = lappend_oid(subclone, constrOid);

src/backend/commands/tablecmds.c

@@ -7704,7 +7704,6 @@ ATAddForeignKeyConstraint(List **wqueue, AlteredTableInfo *tab, Relation rel,
 									  NULL, /* no exclusion constraint */
 									  NULL, /* no check constraint */
 									  NULL,
-									  NULL,
 									  true, /* islocal */
 									  0,	/* inhcount */
 									  true, /* isnoinherit */

src/backend/commands/trigger.c

@@ -752,7 +752,6 @@ CreateTrigger(CreateTrigStmt *stmt, const char *queryString,
 											  NULL, /* no exclusion */
 											  NULL, /* no check constraint */
 											  NULL,
-											  NULL,
 											  true, /* islocal */
 											  0,	/* inhcount */
 											  true, /* isnoinherit */

src/backend/commands/typecmds.c

@@ -3042,7 +3042,6 @@ domainAddConstraint(Oid domainOid, Oid domainNamespace, Oid baseTypeOid,
 					const char *domainName, ObjectAddress *constrAddr)
 {
 	Node	   *expr;
-	char	   *ccsrc;
 	char	   *ccbin;
 	ParseState *pstate;
 	CoerceToDomainValue *domVal;
@@ -3116,12 +3115,6 @@ domainAddConstraint(Oid domainOid, Oid domainNamespace, Oid baseTypeOid,
 	 */
 	ccbin = nodeToString(expr);
 
-	/*
-	 * Deparse it to produce text for consrc.
-	 */
-	ccsrc = deparse_expression(expr,
-							   NIL, false, false);
-
 	/*
 	 * Store the constraint in pg_constraint
 	 */
@@ -3151,7 +3144,6 @@ domainAddConstraint(Oid domainOid, Oid domainNamespace, Oid baseTypeOid,
 							  NULL, /* not an exclusion constraint */
 							  expr, /* Tree form of check constraint */
 							  ccbin,	/* Binary form of check constraint */
-							  ccsrc,	/* Source form of check constraint */
 							  true, /* is local */
 							  0,	/* inhcount */
 							  false,	/* connoinherit */

src/include/catalog/catversion.h

@@ -53,6 +53,6 @@
  */
 
 /*							yyyymmddN */
-#define CATALOG_VERSION_NO	201811011
+#define CATALOG_VERSION_NO	201811012
 
 #endif

src/include/catalog/pg_constraint.h

@@ -142,11 +142,6 @@ CATALOG(pg_constraint,2606,ConstraintRelationId)
 	 * If a check constraint, nodeToString representation of expression
 	 */
 	pg_node_tree conbin;
-
-	/*
-	 * If a check constraint, source-text representation of expression
-	 */
-	text		consrc;
 #endif
 } FormData_pg_constraint;
 
@@ -224,7 +219,6 @@ extern Oid CreateConstraintEntry(const char *constraintName,
 					  const Oid *exclOp,
 					  Node *conExpr,
 					  const char *conBin,
-					  const char *conSrc,
 					  bool conIsLocal,
 					  int conInhCount,
 					  bool conNoInherit,

src/test/regress/expected/inherit.out

@@ -797,7 +797,7 @@ drop table p1;
 CREATE TABLE ac (aa TEXT);
 alter table ac add constraint ac_check check (aa is not null);
 CREATE TABLE bc (bb TEXT) INHERITS (ac);
-select pc.relname, pgc.conname, pgc.contype, pgc.conislocal, pgc.coninhcount, pgc.consrc from pg_class as pc inner join pg_constraint as pgc on (pgc.conrelid = pc.oid) where pc.relname in ('ac', 'bc') order by 1,2;
+select pc.relname, pgc.conname, pgc.contype, pgc.conislocal, pgc.coninhcount, pg_get_expr(pgc.conbin, pc.oid) as consrc from pg_class as pc inner join pg_constraint as pgc on (pgc.conrelid = pc.oid) where pc.relname in ('ac', 'bc') order by 1,2;
  relname | conname  | contype | conislocal | coninhcount |      consrc      
 ---------+----------+---------+------------+-------------+------------------
  ac      | ac_check | c       | t          |           0 | (aa IS NOT NULL)
@@ -813,14 +813,14 @@ DETAIL:  Failing row contains (null, null).
 alter table bc drop constraint ac_check;  -- fail, disallowed
 ERROR:  cannot drop inherited constraint "ac_check" of relation "bc"
 alter table ac drop constraint ac_check;
-select pc.relname, pgc.conname, pgc.contype, pgc.conislocal, pgc.coninhcount, pgc.consrc from pg_class as pc inner join pg_constraint as pgc on (pgc.conrelid = pc.oid) where pc.relname in ('ac', 'bc') order by 1,2;
+select pc.relname, pgc.conname, pgc.contype, pgc.conislocal, pgc.coninhcount, pg_get_expr(pgc.conbin, pc.oid) as consrc from pg_class as pc inner join pg_constraint as pgc on (pgc.conrelid = pc.oid) where pc.relname in ('ac', 'bc') order by 1,2;
  relname | conname | contype | conislocal | coninhcount | consrc 
 ---------+---------+---------+------------+-------------+--------
 (0 rows)
 
 -- try the unnamed-constraint case
 alter table ac add check (aa is not null);
-select pc.relname, pgc.conname, pgc.contype, pgc.conislocal, pgc.coninhcount, pgc.consrc from pg_class as pc inner join pg_constraint as pgc on (pgc.conrelid = pc.oid) where pc.relname in ('ac', 'bc') order by 1,2;
+select pc.relname, pgc.conname, pgc.contype, pgc.conislocal, pgc.coninhcount, pg_get_expr(pgc.conbin, pc.oid) as consrc from pg_class as pc inner join pg_constraint as pgc on (pgc.conrelid = pc.oid) where pc.relname in ('ac', 'bc') order by 1,2;
  relname |   conname   | contype | conislocal | coninhcount |      consrc      
 ---------+-------------+---------+------------+-------------+------------------
  ac      | ac_aa_check | c       | t          |           0 | (aa IS NOT NULL)
@@ -836,14 +836,14 @@ DETAIL:  Failing row contains (null, null).
 alter table bc drop constraint ac_aa_check;  -- fail, disallowed
 ERROR:  cannot drop inherited constraint "ac_aa_check" of relation "bc"
 alter table ac drop constraint ac_aa_check;
-select pc.relname, pgc.conname, pgc.contype, pgc.conislocal, pgc.coninhcount, pgc.consrc from pg_class as pc inner join pg_constraint as pgc on (pgc.conrelid = pc.oid) where pc.relname in ('ac', 'bc') order by 1,2;
+select pc.relname, pgc.conname, pgc.contype, pgc.conislocal, pgc.coninhcount, pg_get_expr(pgc.conbin, pc.oid) as consrc from pg_class as pc inner join pg_constraint as pgc on (pgc.conrelid = pc.oid) where pc.relname in ('ac', 'bc') order by 1,2;
  relname | conname | contype | conislocal | coninhcount | consrc 
 ---------+---------+---------+------------+-------------+--------
 (0 rows)
 
 alter table ac add constraint ac_check check (aa is not null);
 alter table bc no inherit ac;
-select pc.relname, pgc.conname, pgc.contype, pgc.conislocal, pgc.coninhcount, pgc.consrc from pg_class as pc inner join pg_constraint as pgc on (pgc.conrelid = pc.oid) where pc.relname in ('ac', 'bc') order by 1,2;
+select pc.relname, pgc.conname, pgc.contype, pgc.conislocal, pgc.coninhcount, pg_get_expr(pgc.conbin, pc.oid) as consrc from pg_class as pc inner join pg_constraint as pgc on (pgc.conrelid = pc.oid) where pc.relname in ('ac', 'bc') order by 1,2;
  relname | conname  | contype | conislocal | coninhcount |      consrc      
 ---------+----------+---------+------------+-------------+------------------
  ac      | ac_check | c       | t          |           0 | (aa IS NOT NULL)
@@ -851,14 +851,14 @@ select pc.relname, pgc.conname, pgc.contype, pgc.conislocal, pgc.coninhcount, pg
 (2 rows)
 
 alter table bc drop constraint ac_check;
-select pc.relname, pgc.conname, pgc.contype, pgc.conislocal, pgc.coninhcount, pgc.consrc from pg_class as pc inner join pg_constraint as pgc on (pgc.conrelid = pc.oid) where pc.relname in ('ac', 'bc') order by 1,2;
+select pc.relname, pgc.conname, pgc.contype, pgc.conislocal, pgc.coninhcount, pg_get_expr(pgc.conbin, pc.oid) as consrc from pg_class as pc inner join pg_constraint as pgc on (pgc.conrelid = pc.oid) where pc.relname in ('ac', 'bc') order by 1,2;
  relname | conname  | contype | conislocal | coninhcount |      consrc      
 ---------+----------+---------+------------+-------------+------------------
  ac      | ac_check | c       | t          |           0 | (aa IS NOT NULL)
 (1 row)
 
 alter table ac drop constraint ac_check;
-select pc.relname, pgc.conname, pgc.contype, pgc.conislocal, pgc.coninhcount, pgc.consrc from pg_class as pc inner join pg_constraint as pgc on (pgc.conrelid = pc.oid) where pc.relname in ('ac', 'bc') order by 1,2;
+select pc.relname, pgc.conname, pgc.contype, pgc.conislocal, pgc.coninhcount, pg_get_expr(pgc.conbin, pc.oid) as consrc from pg_class as pc inner join pg_constraint as pgc on (pgc.conrelid = pc.oid) where pc.relname in ('ac', 'bc') order by 1,2;
  relname | conname | contype | conislocal | coninhcount | consrc 
 ---------+---------+---------+------------+-------------+--------
 (0 rows)
@@ -869,7 +869,7 @@ create table ac (a int constraint check_a check (a <> 0));
 create table bc (a int constraint check_a check (a <> 0), b int constraint check_b check (b <> 0)) inherits (ac);
 NOTICE:  merging column "a" with inherited definition
 NOTICE:  merging constraint "check_a" with inherited definition
-select pc.relname, pgc.conname, pgc.contype, pgc.conislocal, pgc.coninhcount, pgc.consrc from pg_class as pc inner join pg_constraint as pgc on (pgc.conrelid = pc.oid) where pc.relname in ('ac', 'bc') order by 1,2;
+select pc.relname, pgc.conname, pgc.contype, pgc.conislocal, pgc.coninhcount, pg_get_expr(pgc.conbin, pc.oid) as consrc from pg_class as pc inner join pg_constraint as pgc on (pgc.conrelid = pc.oid) where pc.relname in ('ac', 'bc') order by 1,2;
  relname | conname | contype | conislocal | coninhcount |  consrc  
 ---------+---------+---------+------------+-------------+----------
  ac      | check_a | c       | t          |           0 | (a <> 0)
@@ -882,7 +882,7 @@ drop table ac;
 create table ac (a int constraint check_a check (a <> 0));
 create table bc (b int constraint check_b check (b <> 0));
 create table cc (c int constraint check_c check (c <> 0)) inherits (ac, bc);
-select pc.relname, pgc.conname, pgc.contype, pgc.conislocal, pgc.coninhcount, pgc.consrc from pg_class as pc inner join pg_constraint as pgc on (pgc.conrelid = pc.oid) where pc.relname in ('ac', 'bc', 'cc') order by 1,2;
+select pc.relname, pgc.conname, pgc.contype, pgc.conislocal, pgc.coninhcount, pg_get_expr(pgc.conbin, pc.oid) as consrc from pg_class as pc inner join pg_constraint as pgc on (pgc.conrelid = pc.oid) where pc.relname in ('ac', 'bc', 'cc') order by 1,2;
  relname | conname | contype | conislocal | coninhcount |  consrc  
 ---------+---------+---------+------------+-------------+----------
  ac      | check_a | c       | t          |           0 | (a <> 0)
@@ -893,7 +893,7 @@ select pc.relname, pgc.conname, pgc.contype, pgc.conislocal, pgc.coninhcount, pg
 (5 rows)
 
 alter table cc no inherit bc;
-select pc.relname, pgc.conname, pgc.contype, pgc.conislocal, pgc.coninhcount, pgc.consrc from pg_class as pc inner join pg_constraint as pgc on (pgc.conrelid = pc.oid) where pc.relname in ('ac', 'bc', 'cc') order by 1,2;
+select pc.relname, pgc.conname, pgc.contype, pgc.conislocal, pgc.coninhcount, pg_get_expr(pgc.conbin, pc.oid) as consrc from pg_class as pc inner join pg_constraint as pgc on (pgc.conrelid = pc.oid) where pc.relname in ('ac', 'bc', 'cc') order by 1,2;
  relname | conname | contype | conislocal | coninhcount |  consrc  
 ---------+---------+---------+------------+-------------+----------
  ac      | check_a | c       | t          |           0 | (a <> 0)

src/test/regress/sql/inherit.sql

@@ -257,40 +257,40 @@ drop table p1;
 CREATE TABLE ac (aa TEXT);
 alter table ac add constraint ac_check check (aa is not null);
 CREATE TABLE bc (bb TEXT) INHERITS (ac);
-select pc.relname, pgc.conname, pgc.contype, pgc.conislocal, pgc.coninhcount, pgc.consrc from pg_class as pc inner join pg_constraint as pgc on (pgc.conrelid = pc.oid) where pc.relname in ('ac', 'bc') order by 1,2;
+select pc.relname, pgc.conname, pgc.contype, pgc.conislocal, pgc.coninhcount, pg_get_expr(pgc.conbin, pc.oid) as consrc from pg_class as pc inner join pg_constraint as pgc on (pgc.conrelid = pc.oid) where pc.relname in ('ac', 'bc') order by 1,2;
 
 insert into ac (aa) values (NULL);
 insert into bc (aa) values (NULL);
 
 alter table bc drop constraint ac_check;  -- fail, disallowed
 alter table ac drop constraint ac_check;
-select pc.relname, pgc.conname, pgc.contype, pgc.conislocal, pgc.coninhcount, pgc.consrc from pg_class as pc inner join pg_constraint as pgc on (pgc.conrelid = pc.oid) where pc.relname in ('ac', 'bc') order by 1,2;
+select pc.relname, pgc.conname, pgc.contype, pgc.conislocal, pgc.coninhcount, pg_get_expr(pgc.conbin, pc.oid) as consrc from pg_class as pc inner join pg_constraint as pgc on (pgc.conrelid = pc.oid) where pc.relname in ('ac', 'bc') order by 1,2;
 
 -- try the unnamed-constraint case
 alter table ac add check (aa is not null);
-select pc.relname, pgc.conname, pgc.contype, pgc.conislocal, pgc.coninhcount, pgc.consrc from pg_class as pc inner join pg_constraint as pgc on (pgc.conrelid = pc.oid) where pc.relname in ('ac', 'bc') order by 1,2;
+select pc.relname, pgc.conname, pgc.contype, pgc.conislocal, pgc.coninhcount, pg_get_expr(pgc.conbin, pc.oid) as consrc from pg_class as pc inner join pg_constraint as pgc on (pgc.conrelid = pc.oid) where pc.relname in ('ac', 'bc') order by 1,2;
 
 insert into ac (aa) values (NULL);
 insert into bc (aa) values (NULL);
 
 alter table bc drop constraint ac_aa_check;  -- fail, disallowed
 alter table ac drop constraint ac_aa_check;
-select pc.relname, pgc.conname, pgc.contype, pgc.conislocal, pgc.coninhcount, pgc.consrc from pg_class as pc inner join pg_constraint as pgc on (pgc.conrelid = pc.oid) where pc.relname in ('ac', 'bc') order by 1,2;
+select pc.relname, pgc.conname, pgc.contype, pgc.conislocal, pgc.coninhcount, pg_get_expr(pgc.conbin, pc.oid) as consrc from pg_class as pc inner join pg_constraint as pgc on (pgc.conrelid = pc.oid) where pc.relname in ('ac', 'bc') order by 1,2;
 
 alter table ac add constraint ac_check check (aa is not null);
 alter table bc no inherit ac;
-select pc.relname, pgc.conname, pgc.contype, pgc.conislocal, pgc.coninhcount, pgc.consrc from pg_class as pc inner join pg_constraint as pgc on (pgc.conrelid = pc.oid) where pc.relname in ('ac', 'bc') order by 1,2;
+select pc.relname, pgc.conname, pgc.contype, pgc.conislocal, pgc.coninhcount, pg_get_expr(pgc.conbin, pc.oid) as consrc from pg_class as pc inner join pg_constraint as pgc on (pgc.conrelid = pc.oid) where pc.relname in ('ac', 'bc') order by 1,2;
 alter table bc drop constraint ac_check;
-select pc.relname, pgc.conname, pgc.contype, pgc.conislocal, pgc.coninhcount, pgc.consrc from pg_class as pc inner join pg_constraint as pgc on (pgc.conrelid = pc.oid) where pc.relname in ('ac', 'bc') order by 1,2;
+select pc.relname, pgc.conname, pgc.contype, pgc.conislocal, pgc.coninhcount, pg_get_expr(pgc.conbin, pc.oid) as consrc from pg_class as pc inner join pg_constraint as pgc on (pgc.conrelid = pc.oid) where pc.relname in ('ac', 'bc') order by 1,2;
 alter table ac drop constraint ac_check;
-select pc.relname, pgc.conname, pgc.contype, pgc.conislocal, pgc.coninhcount, pgc.consrc from pg_class as pc inner join pg_constraint as pgc on (pgc.conrelid = pc.oid) where pc.relname in ('ac', 'bc') order by 1,2;
+select pc.relname, pgc.conname, pgc.contype, pgc.conislocal, pgc.coninhcount, pg_get_expr(pgc.conbin, pc.oid) as consrc from pg_class as pc inner join pg_constraint as pgc on (pgc.conrelid = pc.oid) where pc.relname in ('ac', 'bc') order by 1,2;
 
 drop table bc;
 drop table ac;
 
 create table ac (a int constraint check_a check (a <> 0));
 create table bc (a int constraint check_a check (a <> 0), b int constraint check_b check (b <> 0)) inherits (ac);
-select pc.relname, pgc.conname, pgc.contype, pgc.conislocal, pgc.coninhcount, pgc.consrc from pg_class as pc inner join pg_constraint as pgc on (pgc.conrelid = pc.oid) where pc.relname in ('ac', 'bc') order by 1,2;
+select pc.relname, pgc.conname, pgc.contype, pgc.conislocal, pgc.coninhcount, pg_get_expr(pgc.conbin, pc.oid) as consrc from pg_class as pc inner join pg_constraint as pgc on (pgc.conrelid = pc.oid) where pc.relname in ('ac', 'bc') order by 1,2;
 
 drop table bc;
 drop table ac;
@@ -298,10 +298,10 @@ drop table ac;
 create table ac (a int constraint check_a check (a <> 0));
 create table bc (b int constraint check_b check (b <> 0));
 create table cc (c int constraint check_c check (c <> 0)) inherits (ac, bc);
-select pc.relname, pgc.conname, pgc.contype, pgc.conislocal, pgc.coninhcount, pgc.consrc from pg_class as pc inner join pg_constraint as pgc on (pgc.conrelid = pc.oid) where pc.relname in ('ac', 'bc', 'cc') order by 1,2;
+select pc.relname, pgc.conname, pgc.contype, pgc.conislocal, pgc.coninhcount, pg_get_expr(pgc.conbin, pc.oid) as consrc from pg_class as pc inner join pg_constraint as pgc on (pgc.conrelid = pc.oid) where pc.relname in ('ac', 'bc', 'cc') order by 1,2;
 
 alter table cc no inherit bc;
-select pc.relname, pgc.conname, pgc.contype, pgc.conislocal, pgc.coninhcount, pgc.consrc from pg_class as pc inner join pg_constraint as pgc on (pgc.conrelid = pc.oid) where pc.relname in ('ac', 'bc', 'cc') order by 1,2;
+select pc.relname, pgc.conname, pgc.contype, pgc.conislocal, pgc.coninhcount, pg_get_expr(pgc.conbin, pc.oid) as consrc from pg_class as pc inner join pg_constraint as pgc on (pgc.conrelid = pc.oid) where pc.relname in ('ac', 'bc', 'cc') order by 1,2;
 
 drop table cc;
 drop table bc;