Commit 716b8e2d authored by Bruce Momjian's avatar Bruce Momjian

Updates for 6.5.

parent af657ae7
Here are general trigger functions provided as workable examples
of using SPI and triggers. "General" means that functions may be
used for defining triggers for any tables but you have to specify
table/field names (as described below) while creating a trigger.
1. refint.c - functions for implementing referential integrity.
check_primary_key () is to used for foreign keys of a table.
You are to create trigger (BEFORE INSERT OR UPDATE) using this
function on a table referencing another table. You are to specify
as function arguments: triggered table column names which correspond
to foreign key, referenced table name and column names in referenced
table which correspond to primary/unique key.
You may create as many triggers as you need - one trigger for
one reference.
check_foreign_key () is to used for primary/unique keys of a table.
You are to create trigger (BEFORE DELETE OR UPDATE) using this
function on a table referenced by another table(s). You are to specify
as function arguments: number of references for which function has to
performe checking, action if referencing key found ('cascade' - to delete
corresponding foreign key, 'restrict' - to abort transaction if foreign keys
exist, 'setnull' - to set foreign key referencing primary/unique key
being deleted to null), triggered table column names which correspond
to primary/unique key, referencing table name and column names corresponding
to foreign key (, ... - as many referencing tables/keys as specified
by first argument).
Note, that NOT NULL constraint and unique index have to be defined by
youself.
There are examples in refint.example and regression tests
(sql/triggers.sql).
To CREATE FUNCTIONs use refint.sql (will be made by gmake from
refint.source).
# Excuse me for my bad english. Massimo Lambertini
#
#
# New check foreign key
#
I think that cascade mode is to be considered like that the operation over
main table is to be made also in referenced table .
When i Delete , i must delete from referenced table ,
but when i update , i update referenced table and not delete like unmodified refint.c .
I made a new version of refint.c that when i update it check the type of modified key ( if is a text , char() i
added '') and then create a update query that do the right thing .
For my point of view that policy is helpfull because i do not have in referenced table
loss of information .
In preprocessor subdir i have placed a little utility that from a SQL92 table definition,
it create all trigger for foreign key .
the schema that i use to analyze the problem is this
create table
A
( key int4 not null primary key ,...,
) ;
create table
REFERENCED_B
( key int 4 , ... ,
foreign key ( key ) references A --
);
--
-- Trigger for REFERENCED_B
--
CREATE INDEX I_REFERENCED_B_KEY ON REFERENCED_B ( KEY ) ;
CREATE TRIGGER T_P_REFERENCED_B_A BEFORE INSERT OR UPDATE ON REFERENCED_B FOR EACH ROW
EXECUTE PROCEDURE
check_primary_key('KEY','A','KEY' );
CREATE TRIGGER T_F_D_A_REFERENCED_B BEFORE DELETE ON A FOR EACH ROW
EXECUTE PROCEDURE
check_foreign_key(1,'cascade','KEY','REFERENCED_B ','KEY' );
CREATE TRIGGER T_F_U_A_REFERENCED_B AFTER UPDATE ON A FOR EACH ROW
EXECUTE PROCEDURE
check_foreign_key(1,'cascade','KEY','REFERENCED_B ','KEY' );
-- ********************************
I write TRIGGER T_F_U_A_REFERENCED_B ( AFTER ) and not BEFORE because if i set
BEFORE , when i try to modify ( update ) a key of A , i start a execution of TRIGGER T_P_REFERENCED_B_A
( check_primary_key) before the real modification of key in A , then the execution of ( check_primary_key) return
not ok.
With AFTER Clausole i modify first key of A then a update the value of referenced table REFERENCED_B.
Try also the new_example.sql to view the modified policy.
I wish that my explain of problem is quite clear .
If there is miss understanding ( cause my bad english ) please send email to massimo.lambertini@everex.it
......@@ -27,7 +27,7 @@ System Configuration
Operating System (example: Linux 2.0.26 ELF) :
PostgreSQL version (example: PostgreSQL-6.4) : PostgreSQL-6.4
PostgreSQL version (example: PostgreSQL-6.5) : PostgreSQL-6.5
Compiler used (example: gcc 2.8.0) :
......
(1998-09-01)
(1999-05-01)
PostgreSQL has a Web site at http://www.postgresql.org/ which carries details
on the latest release, upcoming features, and other information to make your
work or play with PostgreSQL more productive.
......
#! /usr/local/bin/python
# advanced.py - demo of advanced features of PostGres. Some may not be ANSI.
# inspired from the Postgres tutorial
# adapted to Python 1995 by Pascal Andre
print "__________________________________________________________________"
print "MODULE ADVANCED.PY : ADVANCED POSTGRES SQL COMMANDS TUTORIAL"
print
print "This module is designed for being imported from python prompt"
print
print "In order to run the samples included here, first create a connection"
print "using : cnx = advanced.DB(...)"
print "then start the demo with: advanced.demo(cnx)"
print "__________________________________________________________________"
from pgtools import *
from pg import DB
# inheritance features
def inherit_demo(pgcnx):
print "-----------------------------"
print "-- Inheritance:"
print "-- a table can inherit from zero or more tables. A query"
print "-- can reference either all rows of a table or all rows "
print "-- of a table plus all of its descendants."
print "-----------------------------"
print
print "-- For example, the capitals table inherits from cities table."
print "-- (It inherits all data fields from cities.)"
print
print "CREATE TABLE cities ("
print " name text,"
print " population float8,"
print " altitude int"
print ")"
print
print "CREATE TABLE capitals ("
print " state varchar(2)"
print ") INHERITS (cities)"
pgcnx.query("CREATE TABLE cities (" \
"name text," \
"population float8," \
"altitude int)")
pgcnx.query("CREATE TABLE capitals (" \
"state varchar(2)) INHERITS (cities)")
wait_key()
print
print "-- now, let's populate the tables"
print
print "INSERT INTO cities VALUES ('San Francisco', 7.24E+5, 63)"
print "INSERT INTO cities VALUES ('Las Vegas', 2.583E+5, 2174)"
print "INSERT INTO cities VALUES ('Mariposa', 1200, 1953)"
print
print "INSERT INTO capitals VALUES ('Sacramento', 3.694E+5, 30, 'CA')"
print "INSERT INTO capitals VALUES ('Madison', 1.913E+5, 845, 'WI')"
print
pgcnx.query(
"INSERT INTO cities VALUES ('San Francisco', 7.24E+5, 63)")
pgcnx.query(
"INSERT INTO cities VALUES ('Las Vegas', 2.583E+5, 2174)")
pgcnx.query(
"INSERT INTO cities VALUES ('Mariposa', 1200, 1953)")
pgcnx.query("INSERT INTO capitals" \
" VALUES ('Sacramento', 3.694E+5, 30, 'CA')")
pgcnx.query("INSERT INTO capitals" \
" VALUES ('Madison', 1.913E+5, 845, 'WI')")
print
print "SELECT * FROM cities"
print pgcnx.query("SELECT * FROM cities")
print "SELECT * FROM capitals"
print pgcnx.query("SELECT * FROM capitals")
print
print "-- like before, a regular query references rows of the base"
print "-- table only"
print
print "SELECT name, altitude"
print "FROM cities"
print "WHERE altitude > 500;"
print pgcnx.query("SELECT name, altitude " \
"FROM cities " \
"WHERE altitude > 500")
print
print "-- on the other hand, you can find all cities, including "
print "-- capitals, that are located at an altitude of 500 'ft "
print "-- or higher by:"
print
print "SELECT c.name, c.altitude"
print "FROM cities* c"
print "WHERE c.altitude > 500"
print pgcnx.query("SELECT c.name, c.altitude " \
"FROM cities* c " \
"WHERE c.altitude > 500")
# arrays attributes
def array_demo(pgcnx):
print "----------------------"
print "-- Arrays:"
print "-- attributes can be arrays of base types or user-defined "
print "-- types"
print "----------------------"
print
print "CREATE TABLE sal_emp ("
print " name text,"
print " pay_by_quarter int4[],"
print " schedule text[][]"
print ")"
pgcnx.query("CREATE TABLE sal_emp (" \
"name text," \
"pay_by_quarter int4[]," \
"schedule text[][])")
wait_key()
print
print "-- insert instances with array attributes. "
print " Note the use of braces"
print
print "INSERT INTO sal_emp VALUES ("
print " 'Bill',"
print " '{10000,10000,10000,10000}',"
print " '{{\"meeting\", \"lunch\"}, {}}')"
print
print "INSERT INTO sal_emp VALUES ("
print " 'Carol',"
print " '{20000,25000,25000,25000}',"
print " '{{\"talk\", \"consult\"}, {\"meeting\"}}')"
print
pgcnx.query("INSERT INTO sal_emp VALUES (" \
"'Bill', '{10000,10000,10000,10000}'," \
"'{{\"meeting\", \"lunch\"}, {}}')")
pgcnx.query("INSERT INTO sal_emp VALUES (" \
"'Carol', '{20000,25000,25000,25000}'," \
"'{{\"talk\", \"consult\"}, {\"meeting\"}}')")
wait_key()
print
print "----------------------"
print "-- queries on array attributes"
print "----------------------"
print
print "SELECT name FROM sal_emp WHERE"
print " sal_emp.pay_by_quarter[1] <> sal_emp.pay_by_quarter[2]"
print
print pgcnx.query("SELECT name FROM sal_emp WHERE " \
"sal_emp.pay_by_quarter[1] <> sal_emp.pay_by_quarter[2]")
print
print "-- retrieve third quarter pay of all employees"
print
print "SELECT sal_emp.pay_by_quarter[3] FROM sal_emp"
print
print pgcnx.query("SELECT sal_emp.pay_by_quarter[3] FROM sal_emp")
print
print "-- select subarrays"
print
print "SELECT sal_emp.schedule[1:2][1:1] FROM sal_emp WHERE "
print " sal_emp.name = 'Bill'"
print pgcnx.query("SELECT sal_emp.schedule[1:2][1:1] FROM sal_emp WHERE " \
"sal_emp.name = 'Bill'")
# base cleanup
def demo_cleanup(pgcnx):
print "-- clean up (you must remove the children first)"
print "DROP TABLE sal_emp"
print "DROP TABLE capitals"
print "DROP TABLE cities;"
pgcnx.query("DROP TABLE sal_emp")
pgcnx.query("DROP TABLE capitals")
pgcnx.query("DROP TABLE cities")
# main demo function
def demo(pgcnx):
inherit_demo(pgcnx)
array_demo(pgcnx)
demo_cleanup(pgcnx)
This diff is collapsed.
# func.py - demonstrate the use of SQL functions
# inspired from the PostgreSQL tutorial
# adapted to Python 1995 by Pascal ANDRE
print "__________________________________________________________________"
print "MODULE FUNC.PY : SQL FUNCTION DEFINITION TUTORIAL"
print
print "This module is designed for being imported from python prompt"
print
print "In order to run the samples included here, first create a connection"
print "using : cnx = func.DB(...)"
print "then start the demo with: func.demo(cnx)"
print "__________________________________________________________________"
from pgtools import *
from pg import DB
# basic functions declaration
def base_func(pgcnx):
print "-----------------------------"
print "-- Creating SQL Functions on Base Types"
print "-- a CREATE FUNCTION statement lets you create a new "
print "-- function that can be used in expressions (in SELECT, "
print "-- INSERT, etc.). We will start with functions that "
print "-- return values of base types."
print "-----------------------------"
print
print "--"
print "-- let's create a simple SQL function that takes no arguments"
print "-- and returns 1"
print
print "CREATE FUNCTION one() RETURNS int4"
print " AS 'SELECT 1 as ONE' LANGUAGE 'sql'"
pgcnx.query("CREATE FUNCTION one() RETURNS int4 " \
"AS 'SELECT 1 as ONE' LANGUAGE 'sql'")
wait_key()
print
print "--"
print "-- functions can be used in any expressions (eg. in the target"
print "-- list or qualifications)"
print
print "SELECT one() AS answer"
print pgcnx.query("SELECT one() AS answer")
print
print "--"
print "-- here's how you create a function that takes arguments. The"
print "-- following function returns the sum of its two arguments:"
print
print "CREATE FUNCTION add_em(int4, int4) RETURNS int4"
print " AS 'SELECT $1 + $2' LANGUAGE 'sql'"
pgcnx.query("CREATE FUNCTION add_em(int4, int4) RETURNS int4 " \
"AS 'SELECT $1 + $2' LANGUAGE 'sql'")
print
print "SELECT add_em(1, 2) AS answer"
print pgcnx.query("SELECT add_em(1, 2) AS answer")
# functions on composite types
def comp_func(pgcnx):
print "-----------------------------"
print "-- Creating SQL Functions on Composite Types"
print "-- it is also possible to create functions that return"
print "-- values of composite types."
print "-----------------------------"
print
print "-- before we create more sophisticated functions, let's "
print "-- populate an EMP table"
print
print "CREATE TABLE EMP ("
print " name text,"
print " salary int4,"
print " age int4,"
print " dept varchar(16)"
print ")"
pgcnx.query("CREATE TABLE EMP (" \
"name text," \
"salary int4," \
"age int4," \
"dept varchar(16))")
print
print "INSERT INTO EMP VALUES ('Sam', 1200, 16, 'toy')"
print "INSERT INTO EMP VALUES ('Claire', 5000, 32, 'shoe')"
print "INSERT INTO EMP VALUES ('Andy', -1000, 2, 'candy')"
print "INSERT INTO EMP VALUES ('Bill', 4200, 36, 'shoe')"
print "INSERT INTO EMP VALUES ('Ginger', 4800, 30, 'candy')"
pgcnx.query("INSERT INTO EMP VALUES ('Sam', 1200, 16, 'toy')")
pgcnx.query("INSERT INTO EMP VALUES ('Claire', 5000, 32, 'shoe')")
pgcnx.query("INSERT INTO EMP VALUES ('Andy', -1000, 2, 'candy')")
pgcnx.query("INSERT INTO EMP VALUES ('Bill', 4200, 36, 'shoe')")
pgcnx.query("INSERT INTO EMP VALUES ('Ginger', 4800, 30, 'candy')")
wait_key()
print
print "-- the argument of a function can also be a tuple. For "
print "-- instance, double_salary takes a tuple of the EMP table"
print
print "CREATE FUNCTION double_salary(EMP) RETURNS int4"
print " AS 'SELECT $1.salary * 2 AS salary' LANGUAGE 'sql'"
pgcnx.query("CREATE FUNCTION double_salary(EMP) RETURNS int4 " \
"AS 'SELECT $1.salary * 2 AS salary' LANGUAGE 'sql'")
print
print "SELECT name, double_salary(EMP) AS dream"
print "FROM EMP"
print "WHERE EMP.dept = 'toy'"
print pgcnx.query("SELECT name, double_salary(EMP) AS dream " \
"FROM EMP WHERE EMP.dept = 'toy'")
print
print "-- the return value of a function can also be a tuple. However,"
print "-- make sure that the expressions in the target list is in the "
print "-- same order as the columns of EMP."
print
print "CREATE FUNCTION new_emp() RETURNS EMP"
print " AS 'SELECT \'None\'::text AS name,"
print " 1000 AS salary,"
print " 25 AS age,"
print " \'none\'::varchar(16) AS dept'"
print " LANGUAGE 'sql'"
pgcnx.query("CREATE FUNCTION new_emp() RETURNS EMP " \
"AS 'SELECT \\\'None\\\'::text AS name, " \
"1000 AS salary, " \
"25 AS age, " \
"\\\'none\\\'::varchar(16) AS dept' " \
"LANGUAGE 'sql'")
wait_key()
print
print "-- you can then project a column out of resulting the tuple by"
print "-- using the \"function notation\" for projection columns. "
print "-- (ie. bar(foo) is equivalent to foo.bar) Note that we don't"
print "-- support new_emp().name at this moment."
print
print "SELECT name(new_emp()) AS nobody"
print pgcnx.query("SELECT name(new_emp()) AS nobody")
print
print "-- let's try one more function that returns tuples"
print "CREATE FUNCTION high_pay() RETURNS setof EMP"
print " AS 'SELECT * FROM EMP where salary > 1500'"
print " LANGUAGE 'sql'"
pgcnx.query("CREATE FUNCTION high_pay() RETURNS setof EMP " \
"AS 'SELECT * FROM EMP where salary > 1500' " \
"LANGUAGE 'sql'")
print
print "SELECT name(high_pay()) AS overpaid"
print pgcnx.query("SELECT name(high_pay()) AS overpaid")
# function with multiple SQL commands
def mult_func(pgcnx):
print "-----------------------------"
print "-- Creating SQL Functions with multiple SQL statements"
print "-- you can also create functions that do more than just a"
print "-- SELECT."
print "-----------------------------"
print
print "-- you may have noticed that Andy has a negative salary. We'll"
print "-- create a function that removes employees with negative "
print "-- salaries."
print
print "SELECT * FROM EMP"
print pgcnx.query("SELECT * FROM EMP")
print
print "CREATE FUNCTION clean_EMP () RETURNS int4"
print " AS 'DELETE FROM EMP WHERE EMP.salary <= 0"
print " SELECT 1 AS ignore_this'"
print " LANGUAGE 'sql'"
pgcnx.query("CREATE FUNCTION clean_EMP () RETURNS int4 AS 'DELETE FROM EMP WHERE EMP.salary <= 0; SELECT 1 AS ignore_this' LANGUAGE 'sql'")
print
print "SELECT clean_EMP()"
print pgcnx.query("SELECT clean_EMP()")
print
print "SELECT * FROM EMP"
print pgcnx.query("SELECT * FROM EMP")
# base cleanup
def demo_cleanup(pgcnx):
print "-- remove functions that were created in this file"
print
print "DROP FUNCTION clean_EMP()"
print "DROP FUNCTION high_pay()"
print "DROP FUNCTION new_emp()"
print "DROP FUNCTION add_em(int4, int4)"
print "DROP FUNCTION one()"
print
print "DROP TABLE EMP"
pgcnx.query("DROP FUNCTION clean_EMP()")
pgcnx.query("DROP FUNCTION high_pay()")
pgcnx.query("DROP FUNCTION new_emp()")
pgcnx.query("DROP FUNCTION add_em(int4, int4)")
pgcnx.query("DROP FUNCTION one()")
pgcnx.query("DROP TABLE EMP")
# main demo function
def demo(pgcnx):
base_func(pgcnx)
comp_func(pgcnx)
mult_func(pgcnx)
demo_cleanup(pgcnx)
#! /usr/local/bin/python
# pgtools.py - valuable functions for PostGreSQL tutorial
# written 1995 by Pascal ANDRE
import sys
# number of rows
scr_size = 24
# waits for a key
def wait_key():
print "Press <enter>"
sys.stdin.read(1)
# displays a table for a select query result
def display(fields, result):
print result
# gets cols width
fmt = []
sep = '+'
head = '|'
for i in range(0, len(fields)):
max = len(fields[i])
for j in range(0, len(result)):
if i < len(result[j]):
if len(result[j][i]) > max:
max = len(result[j][i])
fmt.append(" %%%ds |" % max)
for j in range(0, max):
sep = sep + '-'
sep = sep + '--+'
for i in range(0, len(fields)):
head = head + fmt[i] % fields[i]
print sep + '\n' + head + '\n' + sep
pos = 6
for i in range(0, len(result)):
str = '|'
for j in range(0, len(result[i])):
str = str + fmt[j] % result[i][j]
print str
pos = pos + 1
if pos == scr_size:
print sep
wait_key()
print sep + '\n' + head + '\n' + sep
pos = 6
print sep
wait_key()
# syscat.py - parses some system catalogs
# inspired from the PostgreSQL tutorial
# adapted to Python 1995 by Pascal ANDRE
print "____________________________________________________________________"
print
print "MODULE SYSCAT.PY : PARSES SOME POSTGRESQL SYSTEM CATALOGS"
print
print "This module is designed for being imported from python prompt"
print
print "In order to run the samples included here, first create a connection"
print "using : cnx = syscat.DB(...)"
print "then start the demo with: syscat.demo(cnx)"
print
print "Some results may be empty, depending on your base status."
print
print "____________________________________________________________________"
print
from pg import DB
from pgtools import *
# lists all simple indices
def list_simple_ind(pgcnx):
result = pgcnx.query("select bc.relname " \
"as class_name, ic.relname as index_name, a.attname " \
"from pg_class bc, pg_class ic, pg_index i, pg_attribute a " \
"where i.indrelid = bc.oid and i.indexrelid = bc.oid " \
" and i.indkey[0] = a.attnum and a.attrelid = bc.oid " \
" and i.indproc = '0'::oid " \
"order by class_name, index_name, attname")
return result
# list all user defined attributes and their type in user-defined classes
def list_all_attr(pgcnx):
result = pgcnx.query("select c.relname, a.attname, t.typname " \
"from pg_class c, pg_attribute a, pg_type t " \
"where c.relkind = 'r' and c.relname !~ '^pg_' " \
" and c.relname !~ '^Inv' and a.attnum > 0 " \
" and a.attrelid = c.oid and a.atttypid = t.oid " \
"order by relname, attname")
return result
# list all user defined base type
def list_user_base_type(pgcnx):
result = pgcnx.query("select u.usename, t.typname " \
"from pg_type t, pg_user u " \
"where u.usesysid = int2in(int4out(t.typowner)) " \
" and t.typrelid = '0'::oid and t.typelem = '0'::oid " \
" and u.usename <> 'postgres' order by usename, typname")
return result
# list all right-unary operators
def list_right_unary_operator(pgcnx):
result = pgcnx.query("select o.oprname as right_unary, " \
" lt.typname as operand, result.typname as return_type " \
"from pg_operator o, pg_type lt, pg_type result " \
"where o.oprkind='r' and o.oprleft = lt.oid " \
" and o.oprresult = result.oid order by operand")
return result
# list all left-unary operators
def list_left_unary_operator(pgcnx):
result = pgcnx.query("select o.oprname as left_unary, " \
" rt.typname as operand, result.typname as return_type " \
"from pg_operator o, pg_type rt, pg_type result " \
"where o.oprkind='l' and o.oprright = rt.oid " \
" and o.oprresult = result.oid order by operand")
return result
# list all binary operators
def list_binary_operator(pgcnx):
result = pgcnx.query("select o.oprname as binary_op, " \
" rt.typname as right_opr, lt.typname as left_opr, " \
" result.typname as return_type " \
"from pg_operator o, pg_type rt, pg_type lt, pg_type result " \
"where o.oprkind = 'b' and o.oprright = rt.oid " \
" and o.oprleft = lt.oid and o.oprresult = result.oid")
return result
# returns the name, args and return type from all function of lang l
def list_lang_func(pgcnx, l):
result = pgcnx.query("select p.proname, p.pronargs, t.typname " \
"from pg_proc p, pg_language l, pg_type t " \
"where p.prolang = l.oid and p.prorettype = t.oid " \
" and l.lanname = '%s' order by proname" % l)
return result
# lists all the aggregate functions and the type to which they can be applied
def list_agg_func(pgcnx):
result = pgcnx.query("select a.aggname, t.typname " \
"from pg_aggregate a, pg_type t " \
"where a.aggbasetype = t.oid order by aggname, typname")
return result
# lists all the operator classes that can be used with each access method as
# well as the operators that can be used with the respective operator classes
def list_op_class(pgcnx):
result = pgcnx.query("select am.amname, opc.opcname, opr.oprname " \
"from pg_am am, pg_amop amop, pg_opclass opc, pg_operator opr " \
"where amop.amopid = am.oid and amop.amopclaid = opc.oid " \
" and amop.amopopr = opr.oid order by amname, opcname, oprname")
return result
# demo function - runs all examples
def demo(pgcnx):
#import sys, os
#save_stdout = sys.stdout
#sys.stdout = os.popen("more", "w")
print "Listing simple indices ..."
print list_simple_ind(pgcnx)
print "Listing all attributes ..."
print list_all_attr(pgcnx)
print "Listing all user-defined base types ..."
print list_user_base_type(pgcnx)
print "Listing all left-unary operators defined ..."
print list_left_unary_operator(pgcnx)
print "Listing all right-unary operators defined ..."
print list_right_unary_operator(pgcnx)
print "Listing all binary operators ..."
print list_binary_operator(pgcnx)
print "Listing C external function linked ..."
print list_lang_func(pgcnx, 'C')
print "Listing C internal functions ..."
print list_lang_func(pgcnx, 'internal')
print "Listing SQL functions defined ..."
print list_lang_func(pgcnx, 'sql')
print "Listing 'aggregate functions' ..."
print list_agg_func(pgcnx)
print "Listing 'operator classes' ..."
print list_op_class(pgcnx)
#del sys.stdout
#sys.stdout = save_stdout
Markdown is supported
0% or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment