psycopg2

简介

Psycopg 是Python语言的PostgreSQL数据库接口。 它的主要优势在于完全支持Python DB API 2.0，以及安全的多线程支持。它适用于随时创建、销毁大量游标的、和产生大量并发INSERT、UPDATE操作的多线程数据库应用。Psycopg包内含 ZPsycopgDA，一个Zope数据库接口。

示例1：新建表、插入、修改

#-*- coding: utf- -*-
import psycopg2

def main(user,pwd,ip,port,dbname):
    connection = "dbname=%s user=%s password=%s host=%s port=%s" % (dbname, user,pwd, ip, port)

    db = psycopg2.connect(connection)
    cur = db.cursor()
    #创建表
    sql_stat = "CREATE TABLE test_class_id(id INT PRIMARY kEY NOT NULL, test_class TEXT, test_id CHAR(10))";
    cur.execute(sql_stat)
    #插入表
    sql_stat = "insert into test_class_id(id, test_class, test_id) values (1, 'a', '3')"
    cur.execute(sql_stat)

    sql_stat = "insert into test_class_id(id, test_class, test_id) values (2, 'a', '3')"
    cur.execute(sql_stat)
    #更改字段值
    sql_stat = "update test_class_id set test_class='b' where id=1"
    cur.execute(sql_stat)

    db.commit()

if __name__ == "__main__":
    user = '****'
    pwd = '****'
    ip = '***'
    port = ''
    dbname = '****'
    main(user, pwd, ip, port, dbname)
    print "Done~~"

结果

注：这里有多次提交execute  最后一次提交commit，如果没有最后的一次commit，你们前面的提交也是不执行的。

示例2：批量表操作

 -*- coding: utf-8 -*-
import psycopg2

class_ids = []
class_ids.append({"test_id": 1, "test_class":"A", "test_id":""})
class_ids.append({"test_id": 2, "test_class":"A", "test_id":""})
class_ids.append({"test_id": 3, "test_class":"B", "test_id":""})

def main(user,pwd,ip,port,dbname):
    connection = "dbname=%s user=%s password=%s host=%s port=%s" % (dbname, user,pwd, ip, port)
    db = psycopg2.connect(connection)
    cur = db.cursor()

    #sql_del = "delete from cdb_chk_group"
    #cur.execute(sql_del)
    #批量操作
    sql_stat = 'insert into test_class_id(id, test_class, test_id) values (%(test_id)s, %(test_class)s,%(test_id)s)'
    cur.executemany(sql_stat, class_ids)

    db.commit()

if __name__ == "__main__":
    user = '****'
    pwd = '****'
    ip = '****'
    port = '5432'
    dbname = '****'
    main(user, pwd, ip, port, dbname)
    print "Done~~"

验证

用法补充

1. 查询数据，并输出结果

查询一条

>>> cur.execute("select * from test;")
>>> cur.fetchone()
(, , "abc'def")

查询所有条

>>> cur.execute("select * from test;")
>>> cur.fetchall()
[(1, 100, "abc'def"),(2, 100, "abc'def")]