其實在Python中可以用來連接PostgreSQL的模塊很多，這里比較推薦psycopg2。psycopg2安裝起來非常的簡單（pip install psycopg2），這里主要重點(diǎn)介紹下如何使用。
安裝psycopg2模塊：
怎么驗證是否已經(jīng)安裝過psycopy2?
編寫上面代碼，運(yùn)行看是否拋出缺少psycopg2模塊。
安裝方法1：
1)使用psycopg2-2.4.2.win-amd64-py2.7-pg9.0.4-release.exe安裝，下載地址:http://vdisk.weibo.com/s/Cd8pPaw56Ozys
直接運(yùn)行exe，不出錯誤，運(yùn)行上邊代碼驗證代碼無錯誤，基本算是安裝完成了。
2)怎么卸載？
2.1）找到安裝目錄：C:/Python27，發(fā)現(xiàn)下邊包含文件:Removepsycopg2.exe,運(yùn)行，來刪除；
2.2）如果運(yùn)行失敗的話，進(jìn)入目錄：C:/Python27/Lib/site-packages下，找到psycopg2文件夾和psycopg2-2.4.2-py2.7.egg-info文件，右鍵刪除。
2.3）運(yùn)行上邊的代碼，確認(rèn)是否刪除成功。
安裝方法2：
使用.whl安裝，下載地址：https://pypi.python.org/pypi/psycopg2/
下載文件：psycopg2-2.6.2-cp27-none-win_amd64.whl
我這里把psycopg2-2.6.2-cp27-none-win_amd64.whl拷貝到安裝目錄下Scripts文件夾中。
cmd中運(yùn)行代碼：pip install C:/Python27/Scripts/psycopg2-2.6.2-cp27-none-win_amd64.whl
運(yùn)行上邊的代碼，確認(rèn)是否刪除成功。
通過psycopg2操作數(shù)據(jù)庫：
使用賬戶postgres，創(chuàng)建測試數(shù)據(jù)庫testdb。
參考yiibai.comAPI:
S.N. API & 描述
1 psycopg2.connect(database="testdb", user="postgres", password="cohondob", host="127.0.0.1", port="5432")
這個API打開一個連接到PostgreSQL數(shù)據(jù)庫。如果成功打開數(shù)據(jù)庫時，它返回一個連接對象。
2 connection.cursor()
該程序創(chuàng)建一個光標(biāo)將用于整個數(shù)據(jù)庫使用Python編程。
3 cursor.execute(sql [, optional parameters])
此例程執(zhí)行SQL語句?？杀粎?shù)化的SQL語句（即占位符，而不是SQL文字）。 psycopg2的模塊支持占位符用％s標(biāo)志
例如：cursor.execute("insert into people values (%s, %s)", (who, age))
4 curosr.executemany(sql, seq_of_parameters)
該程序執(zhí)行SQL命令對所有參數(shù)序列或序列中的sql映射。
5 curosr.callproc(procname[, parameters])
這個程序執(zhí)行的存儲數(shù)據(jù)庫程序給定的名稱。該程序預(yù)計為每一個參數(shù)，參數(shù)的順序必須包含一個條目。
6 cursor.rowcount
這個只讀屬性，它返回數(shù)據(jù)庫中的行的總數(shù)已修改，插入或刪除最后 execute*().
7 connection.commit()
此方法提交當(dāng)前事務(wù)。如果不調(diào)用這個方法，無論做了什么修改，自從上次調(diào)用commit()是不可見的，從其他的數(shù)據(jù)庫連接。
8 connection.rollback()
此方法會回滾任何更改數(shù)據(jù)庫自上次調(diào)用commit（）方法。
9 connection.close()
此方法關(guān)閉數(shù)據(jù)庫連接。請注意，這并不自動調(diào)用commit（）。如果你只是關(guān)閉數(shù)據(jù)庫連接而不調(diào)用commit（）方法首先，那么所有更改將會丟失！
10 cursor.fetchone()
這種方法提取的查詢結(jié)果集的下一行，返回一個序列，或者無當(dāng)沒有更多的數(shù)據(jù)是可用的。
11 cursor.fetchmany([size=cursor.arraysize])
這個例程中取出下一個組的查詢結(jié)果的行數(shù)，返回一個列表。當(dāng)沒有找到記錄，返回空列表。該方法試圖獲取盡可能多的行所顯示的大小參數(shù)。
12 cursor.fetchall()
這個例程獲取所有查詢結(jié)果（剩余）行，返回一個列表?？招袝r則返回空列表。
打開數(shù)據(jù)庫連接：
import osimport sysimport psycopg2def connectPostgreSQL():conn = psycopg2.connect(database="testdb", user="postgres", password="new.1234", host="127.0.0.1", port="5432")print 'connect successful!'if __name__=='__main__':connectPostgreSQL()
創(chuàng)建表操作：
import osimport sysimport psycopg2def connectPostgreSQL():conn = psycopg2.connect(database="testdb", user="postgres", password="new.1234", host="127.0.0.1", port="5432")print 'connect successful!'cursor=conn.cursor()cursor.execute('''create table public.member(id integer not null primary key,name varchar(32) not null,password varchar(32) not null,singal varchar(128))''')conn.commit()conn.close()print 'table public.member is created!'if __name__=='__main__':connectPostgreSQL()Insert 操作：
import os import sys import psycopg2 def connectPostgreSQL(): conn = psycopg2.connect(database="testdb", user="postgres", password="new.1234", host="127.0.0.1", port="5432") print 'connect successful!' cursor=conn.cursor() cursor.execute('''create table public.member( id integer not null primary key, name varchar(32) not null, password varchar(32) not null, singal varchar(128) )''') conn.commit() conn.close() print 'table public.member is created!' def insertOperate(): conn = psycopg2.connect(database="testdb", user="postgres", password="new.1234", host="127.0.0.1", port="5432") cursor=conn.cursor() cursor.execute("insert into public.member(id,name,password,singal)/ values(1,'member0','password0','signal0')") cursor.execute("insert into public.member(id,name,password,singal)/ values(2,'member1','password1','signal1')") cursor.execute("insert into public.member(id,name,password,singal)/ values(3,'member2','password2','signal2')") cursor.execute("insert into public.member(id,name,password,singal)/ values(4,'member3','password3','signal3')") conn.commit() conn.close() print 'insert records into public.memmber successfully' if __name__=='__main__': #connectPostgreSQL()insertOperate()Select 操作：
import os import sys import psycopg2 def connectPostgreSQL(): conn = psycopg2.connect(database="testdb", user="postgres", password="new.1234", host="127.0.0.1", port="5432") print 'connect successful!' cursor=conn.cursor() cursor.execute('''create table public.member( id integer not null primary key, name varchar(32) not null, password varchar(32) not null, singal varchar(128) )''') conn.commit() conn.close() print 'table public.member is created!' def insertOperate(): conn = psycopg2.connect(database="testdb", user="postgres", password="new.1234", host="127.0.0.1", port="5432") cursor=conn.cursor() cursor.execute("insert into public.member(id,name,password,singal)/ values(1,'member0','password0','signal0')") cursor.execute("insert into public.member(id,name,password,singal)/ values(2,'member1','password1','signal1')") cursor.execute("insert into public.member(id,name,password,singal)/ values(3,'member2','password2','signal2')") cursor.execute("insert into public.member(id,name,password,singal)/ values(4,'member3','password3','signal3')") conn.commit() conn.close() print 'insert records into public.memmber successfully' def selectOperate(): conn = psycopg2.connect(database="testdb", user="postgres", password="new.1234", host="127.0.0.1", port="5432") cursor=conn.cursor() cursor.execute("select id,name,password,singal from public.member where id>2") rows=cursor.fetchall() for row in rows: print 'id=',row[0], ',name=',row[1],',pwd=',row[2],',singal=',row[3],'/n' conn.close() if __name__=='__main__': #connectPostgreSQL() #insertOperate() selectOperate()結(jié)果：
Python 2.7.12 (v2.7.12:d33e0cf91556, Jun 27 2016, 15:24:40) [MSC v.1500 64 bit (AMD64)] on win32Type "copyright", "credits" or "license()" for more information.>>> ========== RESTART: C:/Users/Administrator/Desktop/mutilpleTest.py ==========id= 3 ,name= member2 ,pwd= password2 ,singal= signal2 id= 4 ,name= member3 ,pwd= password3 ,singal= signal3 >>>
update操作：
import os import sys import psycopg2 def connectPostgreSQL(): conn = psycopg2.connect(database="testdb", user="postgres", password="new.1234", host="127.0.0.1", port="5432") print 'connect successful!' cursor=conn.cursor() cursor.execute('''create table public.member( id integer not null primary key, name varchar(32) not null, password varchar(32) not null, singal varchar(128) )''') conn.commit() conn.close() print 'table public.member is created!' def insertOperate(): conn = psycopg2.connect(database="testdb", user="postgres", password="new.1234", host="127.0.0.1", port="5432") cursor=conn.cursor() cursor.execute("insert into public.member(id,name,password,singal)/ values(1,'member0','password0','signal0')") cursor.execute("insert into public.member(id,name,password,singal)/ values(2,'member1','password1','signal1')") cursor.execute("insert into public.member(id,name,password,singal)/ values(3,'member2','password2','signal2')") cursor.execute("insert into public.member(id,name,password,singal)/ values(4,'member3','password3','signal3')") conn.commit() conn.close() print 'insert records into public.memmber successfully' def selectOperate(): conn = psycopg2.connect(database="testdb", user="postgres", password="new.1234", host="127.0.0.1", port="5432") cursor=conn.cursor() cursor.execute("select id,name,password,singal from public.member where id>2") rows=cursor.fetchall() for row in rows: print 'id=',row[0], ',name=',row[1],',pwd=',row[2],',singal=',row[3],'/n' conn.close() def updateOperate(): conn = psycopg2.connect(database="testdb", user="postgres", password="new.1234", host="127.0.0.1", port="5432") cursor=conn.cursor() cursor.execute("update public.member set name='update ...' where id=2") conn.commit() print "Total number of rows updated :", cursor.rowcount cursor.execute("select id,name,password,singal from public.member") rows=cursor.fetchall() for row in rows: print 'id=',row[0], ',name=',row[1],',pwd=',row[2],',singal=',row[3],'/n' conn.close() if __name__=='__main__': #connectPostgreSQL() #insertOperate() #selectOperate() updateOperate()結(jié)果：
Python 2.7.12 (v2.7.12:d33e0cf91556, Jun 27 2016, 15:24:40) [MSC v.1500 64 bit (AMD64)] on win32Type "copyright", "credits" or "license()" for more information.>>> ========== RESTART: C:/Users/Administrator/Desktop/mutilpleTest.py ==========Total number of rows updated : 1id= 1 ,name= member0 ,pwd= password0 ,singal= signal0 id= 3 ,name= member2 ,pwd= password2 ,singal= signal2 id= 4 ,name= member3 ,pwd= password3 ,singal= signal3 id= 2 ,name= update ... ,pwd= password1 ,singal= signal1 >>>
Delete操作：
import os import sys import psycopg2 def connectPostgreSQL(): conn = psycopg2.connect(database="testdb", user="postgres", password="new.1234", host="127.0.0.1", port="5432") print 'connect successful!' cursor=conn.cursor() cursor.execute('''create table public.member( id integer not null primary key, name varchar(32) not null, password varchar(32) not null, singal varchar(128) )''') conn.commit() conn.close() print 'table public.member is created!' def insertOperate(): conn = psycopg2.connect(database="testdb", user="postgres", password="new.1234", host="127.0.0.1", port="5432") cursor=conn.cursor() cursor.execute("insert into public.member(id,name,password,singal)/ values(1,'member0','password0','signal0')") cursor.execute("insert into public.member(id,name,password,singal)/ values(2,'member1','password1','signal1')") cursor.execute("insert into public.member(id,name,password,singal)/ values(3,'member2','password2','signal2')") cursor.execute("insert into public.member(id,name,password,singal)/ values(4,'member3','password3','signal3')") conn.commit() conn.close() print 'insert records into public.memmber successfully' def selectOperate(): conn = psycopg2.connect(database="testdb", user="postgres", password="new.1234", host="127.0.0.1", port="5432") cursor=conn.cursor() cursor.execute("select id,name,password,singal from public.member where id>2") rows=cursor.fetchall() for row in rows: print 'id=',row[0], ',name=',row[1],',pwd=',row[2],',singal=',row[3],'/n' conn.close() def updateOperate(): conn = psycopg2.connect(database="testdb", user="postgres", password="new.1234", host="127.0.0.1", port="5432") cursor=conn.cursor() cursor.execute("update public.member set name='update ...' where id=2") conn.commit() print "Total number of rows updated :", cursor.rowcount cursor.execute("select id,name,password,singal from public.member") rows=cursor.fetchall() for row in rows: print 'id=',row[0], ',name=',row[1],',pwd=',row[2],',singal=',row[3],'/n' conn.close() def deleteOperate(): conn = psycopg2.connect(database="testdb", user="postgres", password="new.1234", host="127.0.0.1", port="5432") cursor=conn.cursor() cursor.execute("select id,name,password,singal from public.member") rows=cursor.fetchall() for row in rows: print 'id=',row[0], ',name=',row[1],',pwd=',row[2],',singal=',row[3],'/n' print 'begin delete' cursor.execute("delete from public.member where id=2") conn.commit() print 'end delete' print "Total number of rows deleted :", cursor.rowcount cursor.execute("select id,name,password,singal from public.member") rows=cursor.fetchall() for row in rows: print 'id=',row[0], ',name=',row[1],',pwd=',row[2],',singal=',row[3],'/n' conn.close() if __name__=='__main__': #connectPostgreSQL() #insertOperate() #selectOperate() #updateOperate() deleteOperate()結(jié)果：
Python 2.7.12 (v2.7.12:d33e0cf91556, Jun 27 2016, 15:24:40) [MSC v.1500 64 bit (AMD64)] on win32Type "copyright", "credits" or "license()" for more information.>>> ========== RESTART: C:/Users/Administrator/Desktop/mutilpleTest.py ==========id= 1 ,name= member0 ,pwd= password0 ,singal= signal0 id= 3 ,name= member2 ,pwd= password2 ,singal= signal2 id= 4 ,name= member3 ,pwd= password3 ,singal= signal3 id= 2 ,name= update ... ,pwd= password1 ,singal= signal1 begin deleteend deleteTotal number of rows deleted : 1id= 1 ,name= member0 ,pwd= password0 ,singal= signal0 id= 3 ,name= member2 ,pwd= password2 ,singal= signal2 id= 4 ,name= member3 ,pwd= password3 ,singal= signal3 >>>
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