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提交 753f720c 编写于 作者: M Marc G. Fournier
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Merge in D'Arcy Cain's python interface (PyGreSQL 2.0)

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src/interfaces/python/Announce 0 → 100644
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Announce : Release of PyGreSQL version 2.0
===============================================
PyGreSQL v2.0 has been released.
It is available at: ftp://ftp.druid.net/pub/distrib/PyGreSQL-2.0.tgz.
PostgreSQL is a database system derived from Postgres4.2. It conforms to
(most of) ANSI SQL and offers many interesting capabilities (C dynamic linking
for functions or type definition, etc.). This package is copyright by the
Regents of the University of California, and is freely distributable.
Python is a interpretated programming langage. It is object oriented, simple
to use (light syntax, simple and straighforward statements), and has many
extensions for building GUIs, interfacing with WWW, etc. An intelligent web
browser (HotJava like) is currently under development (november 1995), and
this should open programmers many doors. Python is copyrighted by Stichting S
Mathematisch Centrum, Amsterdam, The Netherlands, and is freely distributable.
PyGreSQL is a python module that interfaces to a PostgreSQL database. It
embeds the PostgreSQL query library to allow easy use of the powerful
PostgreSQL features from a Python script.
PyGreSQL 2.0 was developed and tested on a NetBSD 1.3_BETA system. It is
based on the PyGres95 code written by Pascal Andre, andre@chimay.via.ecp.fr.
I changed the version to 2.0 and updated the code for Python 1.5 and
PostgreSQL 6.2.1. While I was at it I upgraded the code to use full ANSI
style prototypes and changed the order of arguments to connect.
Important changes from Pygres95 1.0b to PyGreSQL 2.0:
- Updated code for PostgreSQL 6.2.1 and Python 1.5.
- Reformatted code and converted to ANSI .
- Changed name to PyGreSQL (from PyGres95.)
- Changed order of arguments to connect function.
- Created new type pgqueryobject and moved certain methods to it.
- Added a print function for pgqueryobject
- Various code changes - mostly stylistic.
For more information about each package, please have a look to their web pages:
- Python : http://www.python.org/
- PostgreSQL : http://www.PostgreSQL.org/
- PyGreSQL : http://www.druid.net/pygresql/
D'Arcy J.M. Cain
darcy@druid.net
src/interfaces/python/ChangeLog 0 → 100644
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PyGreSQL changelog.
===================
This software is copyright (c) 1995, Pascal Andre (andre@via.ecp.fr)
Further copyright 1997 by D'Arcy J.M. Cain (darcy@druid.net)
See file README for copyright information.
Version 2.0 (23/12/1997):
- updated code for PostgreSQL 6.2.1 and Python 1.5
- reformatted code and converted to ANSI
- Changed name to PyGreSQL (from PyGres95)
- changed order of arguments to connect function
- Created new type pgqueryobject and moved certain methods to it.
- Added a print function for pgqueryobject
Version 1.0b (4/11/1995):
- keyword support for connect function moved from library file to C code
and taken away from library.
- rewrote documentation
- bug fix in connect function
- enhancements in large objects interface methods
Version 1.0a (30/10/1995) (limited release):
- module adapted to standard Python syntax
- keyword support for connect function in library file
- rewrote default parameters interface (internal use of strings)
- fixed minor bugs in module interface
- redefinition of error messages
Version 0.9b (10/10/1995) (first public release):
- large objects implementation
- many bug fixes, enhancments, ...
Version 0.1a (7/10/1995):
- basic libpq functions (SQL access)
src/interfaces/python/README 0 → 100644
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src/interfaces/python/pgext.py 0 → 100644
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from pg import *
# This library file contains some common functions not directly provided by the
# PostGres C library. It offers too a keyword interface for pgmodule connect
# function.
# encapsulate pg connect function for keywords enabling
def doconnect(dbname = None, host = None, port = None, opt = None, tty = None):
return connect(dbname, host, port, opt, tty)
# list all databases on the server
def ListDB(pgcnx):
result = pgcnx.query("select datname from pg_database")
list = []
for node in result:
list.append(result[i][0])
return list
# list all tables (classes) in the selected database
def ListTables(pgcnx):
result = pgcnx.query("select relname from pg_class " \
"where relkind = 'r' " \
" and relname !~ '^Inv' " \
" and relname !~ '^pg_'")
list = []
for node in result:
list.append(node[0])
return list
# list table fields (attribute) in given table
def ListAllFields(pgcnx, table):
result = pgcnx.query("select c.relname, a.attname, t.typname " \
"from pg_class c, pg_attribute a, pg_type t " \
"where c.relname = '%s' " \
" and a.attnum > 0" \
" and a.attrelid = c.oid" \
" and a.atttypid = t.oid " \
"order by relname, attname" % table)
# personnal preference ... so I leave the original query
list = []
for node in result:
list.append(node[1], node[2])
return list
src/interfaces/python/pgmodule.c 0 → 100644
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此差异已折叠。
src/interfaces/python/tutorial/advanced.py 0 → 100755
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#! /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.connect(...)"
print "then start the demo with: advanced.demo(cnx)"
print "__________________________________________________________________"
from pgtools import *
from pgext import *
# 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 char2"
print ") INHERITS (cities)"
pgcnx.query("CREATE TABLE cities (" \
"name text," \
"population float8," \
"altitude int)")
pgcnx.query("CREATE TABLE capitals (" \
"state char2) 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"
q = pgcnx.query("SELECT * FROM cities")
display(q.listfields(), q.getresult())
print "SELECT * FROM capitals"
q = pgcnx.query("SELECT * FROM capitals")
display(q.listfields(), q.getresult())
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;"
q = pgcnx.query("SELECT name, altitude " \
"FROM cities " \
"WHERE altitude > 500")
display(q.listfields(), q.getresult())
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"
q = pgcnx.query("SELECT c.name, c.altitude " \
"FROM cities* c " \
"WHERE c.altitude > 500")
display(q.listfields(), q.getresult())
# time travel features
def time_travel(pgcnx):
print "-----------------------------"
print "-- Time Travel:"
print "-- this feature allows you to run historical queries. "
print "-----------------------------"
print
print "-- first, let's make some changes to the cities table (suppose"
print "-- Mariposa's population grows 10% this year)"
print
print "UPDATE cities"
print "SET population = population * 1.1"
print "WHERE name = 'Mariposa';"
pgcnx.query("UPDATE cities " \
"SET population = population * 1.1" \
"WHERE name = 'Mariposa'")
wait_key()
print
print "-- the default time is the current time ('now'):"
print
print "SELECT * FROM cities WHERE name = 'Mariposa';"
q = pgcnx.query("SELECT * FROM cities WHERE name = 'Mariposa'")
display(q.listfields(), q.getresult())
print
print "-- we can also retrieve the population of Mariposa ever has. "
print "-- ('epoch' is the earliest time representable by the system)"
print
print "SELECT name, population"
print "FROM cities['epoch', 'now'] -- can be abbreviated to cities[,]"
print "WHERE name = 'Mariposa';"
q = pgcnx.query("SELECT name, population "
"FROM cities['epoch', 'now'] "
"WHERE name = 'Mariposa'")
display(q.listfields(), q.getresult())
# 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 char16[][]"
print ")"
pgcnx.query("CREATE TABLE sal_emp (" \
"name text," \
"pay_by_quarter int4[]," \
"schedule char16[][])")
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
q = pgcnx.query("SELECT name FROM sal_emp WHERE " \
"sal_emp.pay_by_quarter[1] <> sal_emp.pay_by_quarter[2]")
display(q.listfields(), q.getresult())
print
print "-- retrieve third quarter pay of all employees"
print
print "SELECT sal_emp.pay_by_quarter[3] FROM sal_emp"
print
q = pgcnx.query("SELECT sal_emp.pay_by_quarter[3] FROM sal_emp")
display(q.listfields(), q.getresult())
print
print "-- select subarrays"
print
print "SELECT sal_emp.schedule[1:2][1:1] FROM sal_emp WHERE "
print " sal_emp.name = 'Bill'"
q = pgcnx.query("SELECT sal_emp.schedule[1:2][1:1] FROM sal_emp WHERE " \
"sal_emp.name = 'Bill'")
display(q.listfields(), q.getresult())
# 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)
time_travel(pgcnx)
array_demo(pgcnx)
demo_cleanup(pgcnx)
src/interfaces/python/tutorial/basics.py 0 → 100755
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#! /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.connect(...)"
print "then start the demo with: basics.demo(cnx)"
print "__________________________________________________________________"
from pgext import *
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 "But that can be easily reformated to :"
display(q.listfields(), q.getresult())
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 :"
q = pgcnx.query("SELECT city, (temp_hi+temp_lo)/2 " \
"AS temp_avg, date FROM weather")
display(q.listfields(), q.getresult())
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"
q = pgcnx.query("SELECT * FROM weather WHERE city = 'San Francisco'" \
" AND prcp > 0.0")
display(q.listfields(), q.getresult())
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;"
q = pgcnx.query("SELECT DISTINCT city FROM weather ORDER BY city")
display(q.listfields(), q.getresult())
# 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"
q = pgcnx.query("SELECT * from temp")
display(q.listfields(), q.getresult())
# 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;"
q = pgcnx.query("SELECT max(temp_lo) FROM weather")
display(q.listfields(), q.getresult())
print
print "-- Aggregate with GROUP BY"
print "SELECT city, max(temp_lo)"
print "FROM weather "
print "GROUP BY city;"
q = pgcnx.query( "SELECT city, max(temp_lo)" \
"FROM weather GROUP BY city")
display(q.listfields(), q.getresult())
# 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
q = 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")
display(q.listfields(), q.getresult())
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
q = pgcnx.query("SELECT city, location, prcp, date FROM weather, cities"\
" WHERE name = city")
display(q.listfields(), q.getresult())
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
q = pgcnx.query("SELECT w.city, c.location, w.prcp, w.date " \
"FROM weather w, cities c WHERE c.name = w.city")
display(q.listfields(), q.getresult())
# 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"
q = pgcnx.query("SELECT * from weather")
display(q.listfields(), q.getresult())
# 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
q = pgcnx.query("SELECT * from weather")
display(q.listfields(), q.getresult())
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"
q = pgcnx.query("SELECT * from weather")
display(q.listfields(), q.getresult())
# 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)
src/interfaces/python/tutorial/func.py 0 → 100755
浏览文件 @ 753f720c
# 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.connect(...)"
print "then start the demo with: func.demo(cnx)"
print "__________________________________________________________________"
from pgtools import *
from pgext import *
# 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"
q = pgcnx.query("SELECT one() AS answer")
display(q.listfields(), q.getresult())
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"
q = pgcnx.query("SELECT add_em(1, 2) AS answer")
display(q.listfields(), q.getresult())
# 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 char16"
print ")"
pgcnx.query("CREATE TABLE EMP (" \
"name text," \
"salary int4," \
"age int4," \
"dept char16)")
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'"
q = pgcnx.query("SELECT name, double_salary(EMP) AS dream " \
"FROM EMP WHERE EMP.dept = 'toy'")
display(q.listfields(), q.getresult())
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\'::char16 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\\\'::char16 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"
q = pgcnx.query("SELECT name(new_emp()) AS nobody")
display(q.listfields(), q.getresult())
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"
q = pgcnx.query("SELECT name(high_pay()) AS overpaid")
display(q.listfields(), q.getresult())
# 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"
q = pgcnx.query("SELECT * FROM EMP")
display(q.listfields(), q.getresult())
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()"
q = pgcnx.query("SELECT clean_EMP()")
display(q.listfields(), q.getresult())
print
print "SELECT * FROM EMP"
q = pgcnx.query("SELECT * FROM EMP")
display(q.listfields(), q.getresult())
# 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)
src/interfaces/python/tutorial/pgtools.py 0 → 100755
浏览文件 @ 753f720c
#! /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):
# 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()
src/interfaces/python/tutorial/syscat.py 0 → 100755
浏览文件 @ 753f720c
# 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.connect(...)"
print "then start the demo with: syscat.demo(cnx)"
print
print "Some results may be empty, depending on your base status."
print
print "If you want to adjust the display to your screen size (rows), you"
print "can type: syscat.src_size = [rows]"
print "____________________________________________________________________"
print
from pgext import *
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):
print "Listing simple indices ..."
temp = list_simple_ind(pgcnx)
display(temp.listfields(), temp.getresult())
print "Listing all attributes ..."
temp = list_all_attr(pgcnx)
display(temp.listfields(), temp.getresult())
print "Listing all user-defined base types ..."
temp = list_user_base_type(pgcnx)
display(temp.listfields(), temp.getresult())
print "Listing all left-unary operators defined ..."
temp = list_left_unary_operator(pgcnx)
display(temp.listfields(), temp.getresult())
print "Listing all right-unary operators defined ..."
temp = list_right_unary_operator(pgcnx)
display(temp.listfields(), temp.getresult())
print "Listing all binary operators ..."
temp = list_binary_operator(pgcnx)
display(temp.listfields(), temp.getresult())
print "Listing C external function linked ..."
temp = list_lang_func(pgcnx, 'C')
display(temp.listfields(), temp.getresult())
print "Listing C internal functions ..."
temp = list_lang_func(pgcnx, 'internal')
display(temp.listfields(), temp.getresult())
print "Listing SQL functions defined ..."
temp = list_lang_func(pgcnx, 'sql')
display(temp.listfields(), temp.getresult())
print "Listing 'aggregate functions' ..."
temp = list_agg_func(pgcnx)
display(temp.listfields(), temp.getresult())
print "Listing 'operator classes' ..."
temp = list_op_class(pgcnx)
display(temp.listfields(), temp.getresult())
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