From 716b8e2dba9b098fb6b9bf6e7304aa238e820f69 Mon Sep 17 00:00:00 2001 From: Bruce Momjian Date: Mon, 17 May 1999 06:06:35 +0000 Subject: [PATCH] Updates for 6.5. --- contrib/spi/README.MAX | 109 ++++++++ doc/bug.template | 2 +- register.txt | 2 +- src/interfaces/python/tutorial/advanced.py | 171 +++++++++++++ src/interfaces/python/tutorial/basics.py | 284 +++++++++++++++++++++ src/interfaces/python/tutorial/func.py | 193 ++++++++++++++ src/interfaces/python/tutorial/pgtools.py | 48 ++++ src/interfaces/python/tutorial/syscat.py | 133 ++++++++++ 8 files changed, 940 insertions(+), 2 deletions(-) create mode 100644 contrib/spi/README.MAX create mode 100755 src/interfaces/python/tutorial/advanced.py create mode 100755 src/interfaces/python/tutorial/basics.py create mode 100755 src/interfaces/python/tutorial/func.py create mode 100755 src/interfaces/python/tutorial/pgtools.py create mode 100755 src/interfaces/python/tutorial/syscat.py diff --git a/contrib/spi/README.MAX b/contrib/spi/README.MAX new file mode 100644 index 0000000000..025ed4925e --- /dev/null +++ b/contrib/spi/README.MAX @@ -0,0 +1,109 @@ + +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 + + + diff --git a/doc/bug.template b/doc/bug.template index c6d1652275..bf62ad60f6 100644 --- a/doc/bug.template +++ b/doc/bug.template @@ -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) : diff --git a/register.txt b/register.txt index e48e787200..9324cdca10 100644 --- a/register.txt +++ b/register.txt @@ -1,6 +1,6 @@ -(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. diff --git a/src/interfaces/python/tutorial/advanced.py b/src/interfaces/python/tutorial/advanced.py new file mode 100755 index 0000000000..4edf1e9294 --- /dev/null +++ b/src/interfaces/python/tutorial/advanced.py @@ -0,0 +1,171 @@ +#! /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) diff --git a/src/interfaces/python/tutorial/basics.py b/src/interfaces/python/tutorial/basics.py new file mode 100755 index 0000000000..418e86bca6 --- /dev/null +++ b/src/interfaces/python/tutorial/basics.py @@ -0,0 +1,284 @@ +#! /usr/local/bin/python +# basics.py - basic SQL commands tutorial +# inspired from the Postgres95 tutorial +# adapted to Python 1995 by Pascal ANDRE + +print "__________________________________________________________________" +print "MODULE BASICS.PY : BASIC 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 = basics.DB(...)" +print "then start the demo with: basics.demo(cnx)" +print "__________________________________________________________________" + +from pg import DB +from pgtools import * + +# table creation commands +def create_table(pgcnx): + print "-----------------------------" + print "-- Creating a table:" + print "-- a CREATE TABLE is used to create base tables. POSTGRES" + print "-- SQL has its own set of built-in types. (Note that" + print "-- keywords are case-insensitive but identifiers are " + print "-- case-sensitive.)" + print "-----------------------------" + print + print "Sending query :" + print "CREATE TABLE weather (" + print " city varchar(80)," + print " temp_lo int," + print " temp_hi int," + print " prcp float8," + print " date date" + print ")" + pgcnx.query("CREATE TABLE weather (city varchar(80), temp_lo int," \ + "temp_hi int, prcp float8, date date)") + print + print "Sending query :" + print "CREATE TABLE cities (" + print " name varchar(80)," + print " location point" + print ")" + pgcnx.query("CREATE TABLE cities (" \ + "name varchar(80)," \ + "location point)") + +# data insertion commands +def insert_data(pgcnx): + print "-----------------------------" + print "-- Inserting data:" + print "-- an INSERT statement is used to insert a new row into" + print "-- a table. There are several ways you can specify what" + print "-- columns the data should go to." + print "-----------------------------" + print + print "-- 1. the simplest case is when the list of value correspond to" + print "-- the order of the columns specified in CREATE TABLE." + print + print "Sending query :" + print "INSERT INTO weather " + print " VALUES ('San Francisco', 46, 50, 0.25, '11/27/1994')" + pgcnx.query("INSERT INTO weather " \ + "VALUES ('San Francisco', 46, 50, 0.25, '11/27/1994')") + print + print "Sending query :" + print "INSERT INTO cities " + print " VALUES ('San Francisco', '(-194.0, 53.0)')" + pgcnx.query("INSERT INTO cities " \ + "VALUES ('San Francisco', '(-194.0, 53.0)')") + print + wait_key() + print "-- 2. you can also specify what column the values correspond " + print " to. (The columns can be specified in any order. You may " + print " also omit any number of columns. eg. unknown precipitation" + print " below)" + print "Sending query :" + print "INSERT INTO weather (city, temp_lo, temp_hi, prcp, date)" + print " VALUES ('San Francisco', 43, 57, 0.0, '11/29/1994')" + pgcnx.query("INSERT INTO weather (date, city, temp_hi, temp_lo)" \ + "VALUES ('11/29/1994', 'Hayward', 54, 37)") + +# direct selection commands +def select_data1(pgcnx): + print "-----------------------------" + print "-- Retrieving data:" + print "-- a SELECT statement is used for retrieving data. The " + print "-- basic syntax is:" + print "-- SELECT columns FROM tables WHERE predicates" + print "-----------------------------" + print + print "-- a simple one would be the query:" + print "SELECT * FROM weather" + print + print "The result is :" + q = pgcnx.query("SELECT * FROM weather") + print q + print + print "-- you may also specify expressions in the target list (the " + print "-- 'AS column' specifies the column name of the result. It is " + print "-- optional.)" + print "The query :" + print " SELECT city, (temp_hi+temp_lo)/2 AS temp_avg, date " + print " FROM weather" + print "Gives :" + print pgcnx.query("SELECT city, (temp_hi+temp_lo)/2 " \ + "AS temp_avg, date FROM weather") + print + print "-- if you want to retrieve rows that satisfy certain condition" + print "-- (ie. a restriction), specify the condition in WHERE. The " + print "-- following retrieves the weather of San Francisco on rainy " + print "-- days." + print "SELECT *" + print "FROM weather" + print "WHERE city = 'San Francisco' " + print " and prcp > 0.0" + print pgcnx.query("SELECT * FROM weather WHERE city = 'San Francisco'" \ + " AND prcp > 0.0") + print + print "-- here is a more complicated one. Duplicates are removed when " + print "-- DISTINCT is specified. ORDER BY specifies the column to sort" + print "-- on. (Just to make sure the following won't confuse you, " + print "-- DISTINCT and ORDER BY can be used separately.)" + print "SELECT DISTINCT city" + print "FROM weather" + print "ORDER BY city;" + print pgcnx.query("SELECT DISTINCT city FROM weather ORDER BY city") + +# selection to a temporary table +def select_data2(pgcnx): + print "-----------------------------" + print "-- Retrieving data into other classes:" + print "-- a SELECT ... INTO statement can be used to retrieve " + print "-- data into another class." + print "-----------------------------" + print + print "The query :" + print "SELECT * INTO TABLE temp " + print "FROM weather" + print "WHERE city = 'San Francisco' " + print " and prcp > 0.0" + pgcnx.query("SELECT * INTO TABLE temp FROM weather " \ + "WHERE city = 'San Francisco' and prcp > 0.0") + print "Fills the table temp, that can be listed with :" + print "SELECT * from temp" + print pgcnx.query("SELECT * from temp") + +# aggregate creation commands +def create_aggregate(pgcnx): + print "-----------------------------" + print "-- Aggregates" + print "-----------------------------" + print + print "Let's consider the query :" + print "SELECT max(temp_lo)" + print "FROM weather;" + print pgcnx.query("SELECT max(temp_lo) FROM weather") + print + print "-- Aggregate with GROUP BY" + 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) diff --git a/src/interfaces/python/tutorial/func.py b/src/interfaces/python/tutorial/func.py new file mode 100755 index 0000000000..d1412620c7 --- /dev/null +++ b/src/interfaces/python/tutorial/func.py @@ -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) diff --git a/src/interfaces/python/tutorial/pgtools.py b/src/interfaces/python/tutorial/pgtools.py new file mode 100755 index 0000000000..5355c584d7 --- /dev/null +++ b/src/interfaces/python/tutorial/pgtools.py @@ -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 " + 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() diff --git a/src/interfaces/python/tutorial/syscat.py b/src/interfaces/python/tutorial/syscat.py new file mode 100755 index 0000000000..79b27ee77c --- /dev/null +++ b/src/interfaces/python/tutorial/syscat.py @@ -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