Updates for 6.5.
This commit is contained in:
Bruce Momjian
parent
af657ae739
commit
716b8e2dba
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Here are general trigger functions provided as workable examples
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of using SPI and triggers. "General" means that functions may be
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used for defining triggers for any tables but you have to specify
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table/field names (as described below) while creating a trigger.
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1. refint.c - functions for implementing referential integrity.
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check_primary_key () is to used for foreign keys of a table.
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You are to create trigger (BEFORE INSERT OR UPDATE) using this
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function on a table referencing another table. You are to specify
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as function arguments: triggered table column names which correspond
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to foreign key, referenced table name and column names in referenced
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table which correspond to primary/unique key.
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You may create as many triggers as you need - one trigger for
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one reference.
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check_foreign_key () is to used for primary/unique keys of a table.
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You are to create trigger (BEFORE DELETE OR UPDATE) using this
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function on a table referenced by another table(s). You are to specify
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as function arguments: number of references for which function has to
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performe checking, action if referencing key found ('cascade' - to delete
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corresponding foreign key, 'restrict' - to abort transaction if foreign keys
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exist, 'setnull' - to set foreign key referencing primary/unique key
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being deleted to null), triggered table column names which correspond
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to primary/unique key, referencing table name and column names corresponding
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to foreign key (, ... - as many referencing tables/keys as specified
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by first argument).
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Note, that NOT NULL constraint and unique index have to be defined by
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youself.
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There are examples in refint.example and regression tests
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(sql/triggers.sql).
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To CREATE FUNCTIONs use refint.sql (will be made by gmake from
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refint.source).
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# Excuse me for my bad english. Massimo Lambertini
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#
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#
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# New check foreign key
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#
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I think that cascade mode is to be considered like that the operation over
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main table is to be made also in referenced table .
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When i Delete , i must delete from referenced table ,
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but when i update , i update referenced table and not delete like unmodified refint.c .
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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
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added '') and then create a update query that do the right thing .
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For my point of view that policy is helpfull because i do not have in referenced table
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loss of information .
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In preprocessor subdir i have placed a little utility that from a SQL92 table definition,
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it create all trigger for foreign key .
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the schema that i use to analyze the problem is this
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create table
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A
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( key int4 not null primary key ,...,
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) ;
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create table
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REFERENCED_B
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( key int 4 , ... ,
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foreign key ( key ) references A --
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);
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--
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-- Trigger for REFERENCED_B
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--
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CREATE INDEX I_REFERENCED_B_KEY ON REFERENCED_B ( KEY ) ;
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CREATE TRIGGER T_P_REFERENCED_B_A BEFORE INSERT OR UPDATE ON REFERENCED_B FOR EACH ROW
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EXECUTE PROCEDURE
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check_primary_key('KEY','A','KEY' );
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CREATE TRIGGER T_F_D_A_REFERENCED_B BEFORE DELETE ON A FOR EACH ROW
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EXECUTE PROCEDURE
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check_foreign_key(1,'cascade','KEY','REFERENCED_B ','KEY' );
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CREATE TRIGGER T_F_U_A_REFERENCED_B AFTER UPDATE ON A FOR EACH ROW
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EXECUTE PROCEDURE
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check_foreign_key(1,'cascade','KEY','REFERENCED_B ','KEY' );
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-- ********************************
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I write TRIGGER T_F_U_A_REFERENCED_B ( AFTER ) and not BEFORE because if i set
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BEFORE , when i try to modify ( update ) a key of A , i start a execution of TRIGGER T_P_REFERENCED_B_A
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( check_primary_key) before the real modification of key in A , then the execution of ( check_primary_key) return
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not ok.
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With AFTER Clausole i modify first key of A then a update the value of referenced table REFERENCED_B.
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Try also the new_example.sql to view the modified policy.
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I wish that my explain of problem is quite clear .
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If there is miss understanding ( cause my bad english ) please send email to massimo.lambertini@everex.it
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@ -27,7 +27,7 @@ System Configuration
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Operating System (example: Linux 2.0.26 ELF) :
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PostgreSQL version (example: PostgreSQL-6.4) : PostgreSQL-6.4
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PostgreSQL version (example: PostgreSQL-6.5) : PostgreSQL-6.5
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Compiler used (example: gcc 2.8.0) :
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@ -1,6 +1,6 @@
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(1998-09-01)
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(1999-05-01)
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PostgreSQL has a Web site at http://www.postgresql.org/ which carries details
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on the latest release, upcoming features, and other information to make your
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work or play with PostgreSQL more productive.
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@ -0,0 +1,171 @@
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#! /usr/local/bin/python
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# advanced.py - demo of advanced features of PostGres. Some may not be ANSI.
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# inspired from the Postgres tutorial
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# adapted to Python 1995 by Pascal Andre
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print "__________________________________________________________________"
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print "MODULE ADVANCED.PY : ADVANCED POSTGRES SQL COMMANDS TUTORIAL"
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print
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print "This module is designed for being imported from python prompt"
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print
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print "In order to run the samples included here, first create a connection"
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print "using : cnx = advanced.DB(...)"
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print "then start the demo with: advanced.demo(cnx)"
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print "__________________________________________________________________"
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from pgtools import *
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from pg import DB
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# inheritance features
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def inherit_demo(pgcnx):
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print "-----------------------------"
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print "-- Inheritance:"
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print "-- a table can inherit from zero or more tables. A query"
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print "-- can reference either all rows of a table or all rows "
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print "-- of a table plus all of its descendants."
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print "-----------------------------"
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print
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print "-- For example, the capitals table inherits from cities table."
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print "-- (It inherits all data fields from cities.)"
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print
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print "CREATE TABLE cities ("
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print " name text,"
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print " population float8,"
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print " altitude int"
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print ")"
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print
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print "CREATE TABLE capitals ("
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print " state varchar(2)"
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print ") INHERITS (cities)"
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pgcnx.query("CREATE TABLE cities (" \
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"name text," \
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"population float8," \
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"altitude int)")
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pgcnx.query("CREATE TABLE capitals (" \
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"state varchar(2)) INHERITS (cities)")
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wait_key()
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print
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print "-- now, let's populate the tables"
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print
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print "INSERT INTO cities VALUES ('San Francisco', 7.24E+5, 63)"
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print "INSERT INTO cities VALUES ('Las Vegas', 2.583E+5, 2174)"
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print "INSERT INTO cities VALUES ('Mariposa', 1200, 1953)"
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print
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print "INSERT INTO capitals VALUES ('Sacramento', 3.694E+5, 30, 'CA')"
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print "INSERT INTO capitals VALUES ('Madison', 1.913E+5, 845, 'WI')"
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print
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pgcnx.query(
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"INSERT INTO cities VALUES ('San Francisco', 7.24E+5, 63)")
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pgcnx.query(
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"INSERT INTO cities VALUES ('Las Vegas', 2.583E+5, 2174)")
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pgcnx.query(
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"INSERT INTO cities VALUES ('Mariposa', 1200, 1953)")
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pgcnx.query("INSERT INTO capitals" \
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" VALUES ('Sacramento', 3.694E+5, 30, 'CA')")
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pgcnx.query("INSERT INTO capitals" \
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" VALUES ('Madison', 1.913E+5, 845, 'WI')")
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print
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print "SELECT * FROM cities"
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print pgcnx.query("SELECT * FROM cities")
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print "SELECT * FROM capitals"
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print pgcnx.query("SELECT * FROM capitals")
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print
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print "-- like before, a regular query references rows of the base"
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print "-- table only"
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print
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print "SELECT name, altitude"
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print "FROM cities"
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print "WHERE altitude > 500;"
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print pgcnx.query("SELECT name, altitude " \
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"FROM cities " \
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"WHERE altitude > 500")
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print
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print "-- on the other hand, you can find all cities, including "
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print "-- capitals, that are located at an altitude of 500 'ft "
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print "-- or higher by:"
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print
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print "SELECT c.name, c.altitude"
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print "FROM cities* c"
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print "WHERE c.altitude > 500"
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print pgcnx.query("SELECT c.name, c.altitude " \
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"FROM cities* c " \
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"WHERE c.altitude > 500")
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# arrays attributes
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def array_demo(pgcnx):
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print "----------------------"
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print "-- Arrays:"
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print "-- attributes can be arrays of base types or user-defined "
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print "-- types"
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print "----------------------"
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print
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print "CREATE TABLE sal_emp ("
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print " name text,"
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print " pay_by_quarter int4[],"
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print " schedule text[][]"
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print ")"
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pgcnx.query("CREATE TABLE sal_emp (" \
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"name text," \
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"pay_by_quarter int4[]," \
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"schedule text[][])")
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wait_key()
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print
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print "-- insert instances with array attributes. "
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print " Note the use of braces"
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print
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print "INSERT INTO sal_emp VALUES ("
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print " 'Bill',"
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print " '{10000,10000,10000,10000}',"
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print " '{{\"meeting\", \"lunch\"}, {}}')"
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print
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print "INSERT INTO sal_emp VALUES ("
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print " 'Carol',"
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print " '{20000,25000,25000,25000}',"
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print " '{{\"talk\", \"consult\"}, {\"meeting\"}}')"
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print
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pgcnx.query("INSERT INTO sal_emp VALUES (" \
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"'Bill', '{10000,10000,10000,10000}'," \
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"'{{\"meeting\", \"lunch\"}, {}}')")
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pgcnx.query("INSERT INTO sal_emp VALUES (" \
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"'Carol', '{20000,25000,25000,25000}'," \
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"'{{\"talk\", \"consult\"}, {\"meeting\"}}')")
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wait_key()
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print
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print "----------------------"
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print "-- queries on array attributes"
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print "----------------------"
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print
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print "SELECT name FROM sal_emp WHERE"
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print " sal_emp.pay_by_quarter[1] <> sal_emp.pay_by_quarter[2]"
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print
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print pgcnx.query("SELECT name FROM sal_emp WHERE " \
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"sal_emp.pay_by_quarter[1] <> sal_emp.pay_by_quarter[2]")
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print
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print "-- retrieve third quarter pay of all employees"
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print
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print "SELECT sal_emp.pay_by_quarter[3] FROM sal_emp"
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print
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print pgcnx.query("SELECT sal_emp.pay_by_quarter[3] FROM sal_emp")
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print
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print "-- select subarrays"
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print
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print "SELECT sal_emp.schedule[1:2][1:1] FROM sal_emp WHERE "
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print " sal_emp.name = 'Bill'"
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print pgcnx.query("SELECT sal_emp.schedule[1:2][1:1] FROM sal_emp WHERE " \
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"sal_emp.name = 'Bill'")
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# base cleanup
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def demo_cleanup(pgcnx):
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print "-- clean up (you must remove the children first)"
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print "DROP TABLE sal_emp"
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print "DROP TABLE capitals"
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print "DROP TABLE cities;"
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pgcnx.query("DROP TABLE sal_emp")
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pgcnx.query("DROP TABLE capitals")
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pgcnx.query("DROP TABLE cities")
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# main demo function
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def demo(pgcnx):
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inherit_demo(pgcnx)
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array_demo(pgcnx)
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demo_cleanup(pgcnx)
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@ -0,0 +1,284 @@
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#! /usr/local/bin/python
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# basics.py - basic SQL commands tutorial
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# inspired from the Postgres95 tutorial
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# adapted to Python 1995 by Pascal ANDRE
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print "__________________________________________________________________"
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print "MODULE BASICS.PY : BASIC SQL COMMANDS TUTORIAL"
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print
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print "This module is designed for being imported from python prompt"
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print
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print "In order to run the samples included here, first create a connection"
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print "using : cnx = basics.DB(...)"
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print "then start the demo with: basics.demo(cnx)"
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print "__________________________________________________________________"
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from pg import DB
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from pgtools import *
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# table creation commands
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def create_table(pgcnx):
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print "-----------------------------"
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print "-- Creating a table:"
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print "-- a CREATE TABLE is used to create base tables. POSTGRES"
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print "-- SQL has its own set of built-in types. (Note that"
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print "-- keywords are case-insensitive but identifiers are "
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print "-- case-sensitive.)"
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print "-----------------------------"
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print
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print "Sending query :"
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print "CREATE TABLE weather ("
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print " city varchar(80),"
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print " temp_lo int,"
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print " temp_hi int,"
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print " prcp float8,"
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print " date date"
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print ")"
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pgcnx.query("CREATE TABLE weather (city varchar(80), temp_lo int," \
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"temp_hi int, prcp float8, date date)")
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print
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print "Sending query :"
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print "CREATE TABLE cities ("
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print " name varchar(80),"
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print " location point"
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print ")"
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pgcnx.query("CREATE TABLE cities (" \
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"name varchar(80)," \
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"location point)")
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# data insertion commands
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def insert_data(pgcnx):
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print "-----------------------------"
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print "-- Inserting data:"
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print "-- an INSERT statement is used to insert a new row into"
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print "-- a table. There are several ways you can specify what"
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print "-- columns the data should go to."
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print "-----------------------------"
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print
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print "-- 1. the simplest case is when the list of value correspond to"
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print "-- the order of the columns specified in CREATE TABLE."
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print
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print "Sending query :"
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print "INSERT INTO weather "
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print " VALUES ('San Francisco', 46, 50, 0.25, '11/27/1994')"
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pgcnx.query("INSERT INTO weather " \
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"VALUES ('San Francisco', 46, 50, 0.25, '11/27/1994')")
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print
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print "Sending query :"
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print "INSERT INTO cities "
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print " VALUES ('San Francisco', '(-194.0, 53.0)')"
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pgcnx.query("INSERT INTO cities " \
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"VALUES ('San Francisco', '(-194.0, 53.0)')")
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print
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wait_key()
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print "-- 2. you can also specify what column the values correspond "
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print " to. (The columns can be specified in any order. You may "
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print " also omit any number of columns. eg. unknown precipitation"
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print " below)"
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print "Sending query :"
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print "INSERT INTO weather (city, temp_lo, temp_hi, prcp, date)"
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print " VALUES ('San Francisco', 43, 57, 0.0, '11/29/1994')"
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pgcnx.query("INSERT INTO weather (date, city, temp_hi, temp_lo)" \
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"VALUES ('11/29/1994', 'Hayward', 54, 37)")
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# direct selection commands
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def select_data1(pgcnx):
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print "-----------------------------"
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print "-- Retrieving data:"
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print "-- a SELECT statement is used for retrieving data. The "
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print "-- basic syntax is:"
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print "-- SELECT columns FROM tables WHERE predicates"
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print "-----------------------------"
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print
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print "-- a simple one would be the query:"
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print "SELECT * FROM weather"
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print
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print "The result is :"
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q = pgcnx.query("SELECT * FROM weather")
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print q
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print
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print "-- you may also specify expressions in the target list (the "
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print "-- 'AS column' specifies the column name of the result. It is "
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print "-- optional.)"
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print "The query :"
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print " SELECT city, (temp_hi+temp_lo)/2 AS temp_avg, date "
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print " FROM weather"
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print "Gives :"
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print pgcnx.query("SELECT city, (temp_hi+temp_lo)/2 " \
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"AS temp_avg, date FROM weather")
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print
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print "-- if you want to retrieve rows that satisfy certain condition"
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print "-- (ie. a restriction), specify the condition in WHERE. The "
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print "-- following retrieves the weather of San Francisco on rainy "
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print "-- days."
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print "SELECT *"
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print "FROM weather"
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print "WHERE city = 'San Francisco' "
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print " and prcp > 0.0"
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print pgcnx.query("SELECT * FROM weather WHERE city = 'San Francisco'" \
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" AND prcp > 0.0")
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print
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print "-- here is a more complicated one. Duplicates are removed when "
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print "-- DISTINCT is specified. ORDER BY specifies the column to sort"
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print "-- on. (Just to make sure the following won't confuse you, "
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print "-- DISTINCT and ORDER BY can be used separately.)"
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print "SELECT DISTINCT city"
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print "FROM weather"
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print "ORDER BY city;"
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print pgcnx.query("SELECT DISTINCT city FROM weather ORDER BY city")
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# selection to a temporary table
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def select_data2(pgcnx):
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print "-----------------------------"
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print "-- Retrieving data into other classes:"
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print "-- a SELECT ... INTO statement can be used to retrieve "
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print "-- data into another class."
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print "-----------------------------"
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print
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print "The query :"
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print "SELECT * INTO TABLE temp "
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print "FROM weather"
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print "WHERE city = 'San Francisco' "
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print " and prcp > 0.0"
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pgcnx.query("SELECT * INTO TABLE temp FROM weather " \
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"WHERE city = 'San Francisco' and prcp > 0.0")
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print "Fills the table temp, that can be listed with :"
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print "SELECT * from temp"
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print pgcnx.query("SELECT * from temp")
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# aggregate creation commands
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def create_aggregate(pgcnx):
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print "-----------------------------"
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print "-- Aggregates"
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print "-----------------------------"
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print
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print "Let's consider the query :"
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print "SELECT max(temp_lo)"
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print "FROM weather;"
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print pgcnx.query("SELECT max(temp_lo) FROM weather")
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print
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print "-- Aggregate with GROUP BY"
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||||
print "SELECT city, max(temp_lo)"
|
||||
print "FROM weather "
|
||||
print "GROUP BY city;"
|
||||
print pgcnx.query( "SELECT city, max(temp_lo)" \
|
||||
"FROM weather GROUP BY city")
|
||||
|
||||
# table join commands
|
||||
def join_table(pgcnx):
|
||||
print "-----------------------------"
|
||||
print "-- Joining tables:"
|
||||
print "-- queries can access multiple tables at once or access"
|
||||
print "-- the same table in such a way that multiple instances"
|
||||
print "-- of the table are being processed at the same time."
|
||||
print "-----------------------------"
|
||||
print
|
||||
print "-- suppose we want to find all the records that are in the "
|
||||
print "-- temperature range of other records. W1 and W2 are aliases "
|
||||
print "--for weather."
|
||||
print
|
||||
print "SELECT W1.city, W1.temp_lo, W1.temp_hi, "
|
||||
print " W2.city, W2.temp_lo, W2.temp_hi"
|
||||
print "FROM weather W1, weather W2"
|
||||
print "WHERE W1.temp_lo < W2.temp_lo "
|
||||
print " and W1.temp_hi > W2.temp_hi"
|
||||
print
|
||||
print pgcnx.query("SELECT W1.city, W1.temp_lo, W1.temp_hi, " \
|
||||
"W2.city, W2.temp_lo, W2.temp_hi FROM weather W1, weather W2 "\
|
||||
"WHERE W1.temp_lo < W2.temp_lo and W1.temp_hi > W2.temp_hi")
|
||||
print
|
||||
print "-- let's join two tables. The following joins the weather table"
|
||||
print "-- and the cities table."
|
||||
print
|
||||
print "SELECT city, location, prcp, date"
|
||||
print "FROM weather, cities"
|
||||
print "WHERE name = city"
|
||||
print
|
||||
print pgcnx.query("SELECT city, location, prcp, date FROM weather, cities"\
|
||||
" WHERE name = city")
|
||||
print
|
||||
print "-- since the column names are all different, we don't have to "
|
||||
print "-- specify the table name. If you want to be clear, you can do "
|
||||
print "-- the following. They give identical results, of course."
|
||||
print
|
||||
print "SELECT w.city, c.location, w.prcp, w.date"
|
||||
print "FROM weather w, cities c"
|
||||
print "WHERE c.name = w.city;"
|
||||
print
|
||||
print pgcnx.query("SELECT w.city, c.location, w.prcp, w.date " \
|
||||
"FROM weather w, cities c WHERE c.name = w.city")
|
||||
|
||||
# data updating commands
|
||||
def update_data(pgcnx):
|
||||
print "-----------------------------"
|
||||
print "-- Updating data:"
|
||||
print "-- an UPDATE statement is used for updating data. "
|
||||
print "-----------------------------"
|
||||
print
|
||||
print "-- suppose you discover the temperature readings are all off by"
|
||||
print "-- 2 degrees as of Nov 28, you may update the data as follow:"
|
||||
print
|
||||
print "UPDATE weather"
|
||||
print " SET temp_hi = temp_hi - 2, temp_lo = temp_lo - 2"
|
||||
print " WHERE date > '11/28/1994'"
|
||||
print
|
||||
pgcnx.query("UPDATE weather " \
|
||||
"SET temp_hi = temp_hi - 2, temp_lo = temp_lo - 2" \
|
||||
"WHERE date > '11/28/1994'")
|
||||
print
|
||||
print "SELECT * from weather"
|
||||
print pgcnx.query("SELECT * from weather")
|
||||
|
||||
# data deletion commands
|
||||
def delete_data(pgcnx):
|
||||
print "-----------------------------"
|
||||
print "-- Deleting data:"
|
||||
print "-- a DELETE statement is used for deleting rows from a "
|
||||
print "-- table."
|
||||
print "-----------------------------"
|
||||
print
|
||||
print "-- suppose you are no longer interested in the weather of "
|
||||
print "-- Hayward, you can do the following to delete those rows from"
|
||||
print "-- the table"
|
||||
print
|
||||
print "DELETE FROM weather WHERE city = 'Hayward'"
|
||||
pgcnx.query("DELETE FROM weather WHERE city = 'Hayward'")
|
||||
print
|
||||
print "SELECT * from weather"
|
||||
print
|
||||
print pgcnx.query("SELECT * from weather")
|
||||
print
|
||||
print "-- you can also delete all the rows in a table by doing the "
|
||||
print "-- following. (This is different from DROP TABLE which removes "
|
||||
print "-- the table in addition to the removing the rows.)"
|
||||
print
|
||||
print "DELETE FROM weather"
|
||||
pgcnx.query("DELETE FROM weather")
|
||||
print
|
||||
print "SELECT * from weather"
|
||||
print pgcnx.query("SELECT * from weather")
|
||||
|
||||
# table removal commands
|
||||
def remove_table(pgcnx):
|
||||
print "-----------------------------"
|
||||
print "-- Removing the tables:"
|
||||
print "-- DROP TABLE is used to remove tables. After you have"
|
||||
print "-- done this, you can no longer use those tables."
|
||||
print "-----------------------------"
|
||||
print
|
||||
print "DROP TABLE weather, cities, temp"
|
||||
pgcnx.query("DROP TABLE weather, cities, temp")
|
||||
|
||||
# main demo function
|
||||
def demo(pgcnx):
|
||||
create_table(pgcnx)
|
||||
wait_key()
|
||||
insert_data(pgcnx)
|
||||
wait_key()
|
||||
select_data1(pgcnx)
|
||||
select_data2(pgcnx)
|
||||
create_aggregate(pgcnx)
|
||||
join_table(pgcnx)
|
||||
update_data(pgcnx)
|
||||
delete_data(pgcnx)
|
||||
remove_table(pgcnx)
|
||||
|
|
@ -0,0 +1,193 @@
|
|||
# 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)
|
||||
|
|
@ -0,0 +1,48 @@
|
|||
#! /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()
|
||||
|
|
@ -0,0 +1,133 @@
|
|||
# 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
|
||||
Loading…
Reference in New Issue