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python 连接各类主流数据库简单示例

来源：程序员人生发布时间：2016-06-17 08:27:00 阅读次数：3073次

本篇博文主要介绍Python连接各种数据库的方法及简单使用
包括关系数据库：sqlite,mysql,mssql
非关系数据库：MongoDB,Redis

代码写的比较清楚，直接上代码

1.连接sqlite

# coding=utf⑻
# http://www.runoob.com/sqlite/sqlite-python.html
import sqlite3
import traceback

try:
    # 如果表不存在,就创建
    with sqlite3.connect('test.db') as conn:

        print("Opened database successfully")

        # 删除表
        conn.execute("DROP TABLE IF EXISTS  COMPANY")

        # 创建表
        sql = """
                 CREATE TABLE IF NOT EXISTS COMPANY
               (ID INTEGER  PRIMARY KEY       AUTOINCREMENT,
               NAME           TEXT    NOT NULL,
               AGE            INT     NOT NULL,
               ADDRESS        CHAR(50),
               SALARY         REAL);
        """
        conn.execute(sql)

        print("create table successfully")

        # 添加数据
        conn.executemany("INSERT INTO COMPANY (NAME,AGE,ADDRESS,SALARY) VALUES (?, ?, ?, ? )",
                         [('Paul', 32, 'California', 20000.00),
                          ('Allen', 25, 'Texas', 15000.00),
                          ('Teddy', 23, 'Norway', 20000.00),
                          ('Mark', 25, 'Rich-Mond ', 65000.00),
                          ('David', 27, 'Texas', 85000.00),
                          ('Kim', 22, 'South-Hall', 45000.00),
                          ('James', 24, 'Houston', 10000.00)])
        # conn.execute("INSERT INTO COMPANY (NAME,AGE,ADDRESS,SALARY)\
        # VALUES ( 'Paul', 32, 'California', 20000.00 )")
        #
        # conn.execute("INSERT INTO COMPANY (NAME,AGE,ADDRESS,SALARY)\
        # VALUES ('Allen', 25, 'Texas', 15000.00 )")
        #
        # conn.execute("INSERT INTO COMPANY (NAME,AGE,ADDRESS,SALARY)\
        # VALUES ('Teddy', 23, 'Norway', 20000.00 )")
        #
        # conn.execute("INSERT INTO COMPANY (NAME,AGE,ADDRESS,SALARY)\
        # VALUES ( 'Mark', 25, 'Rich-Mond ', 65000.00 )")
        #
        # conn.execute("INSERT INTO COMPANY (NAME,AGE,ADDRESS,SALARY)\
        # VALUES ( 'David', 27, 'Texas', 85000.00 )");
        #
        # conn.execute("INSERT INTO COMPANY (NAME,AGE,ADDRESS,SALARY)\
        # VALUES ( 'Kim', 22, 'South-Hall', 45000.00 )")
        #
        # conn.execute("INSERT INTO COMPANY (NAME,AGE,ADDRESS,SALARY)\
        # VALUES ( 'James', 24, 'Houston', 10000.00 )")

        # 提交,否则重新运行程序时,表中无数据
        conn.commit()
        print("insert successfully")

        # 查询表
        sql = """
            select id,NAME,AGE,ADDRESS,SALARY FROM COMPANY
         """

        result = conn.execute(sql)

        for row in result:
            print("-" * 50)  # 输出50个-,作为分界限
            print("%⑴0s %s" % ("id", row[0]))  # 字段名固定10位宽度,并且左对齐
            print("%⑴0s %s" % ("name", row[1]))
            print("%⑴0s %s" % ("age", row[2]))
            print("%⑴0s %s" % ("address", row[3]))
            print("%⑴0s %.2f" % ("salary", row[4]))
            # or
            # print('{:10s} {:.2f}'.format("salary", row[4]))


except sqlite3.Error as e:
    print("sqlite3 Error:", e)
    traceback.print_exc()

2.连接mysql

2.1使用mysqldb库中的_mysql

#! /usr/bin/env python2.7
# coding=utf⑻
# Created by xiaosanyu at 16/5/30

# mysqldb 只支持python2.7
# http://mysql-python.sourceforge.net/

import MySQLdb
from contextlib import closing
import traceback

try:
    # 获得1个数据库连接
    with closing(MySQLdb.connect(host='localhost', user='root', passwd='root', db='test', port=3306,charset='utf8')) as conn:
        print("connect database successfully")
        with closing(conn.cursor()) as cur:
            # 删除表
            cur.execute("DROP TABLE IF EXISTS  COMPANY")
            # 创建表
            sql = """
                     CREATE TABLE IF NOT EXISTS COMPANY
                   (ID INTEGER  PRIMARY KEY NOT NULL  auto_increment,
                   NAME           TEXT    NOT NULL,
                   AGE            INT     NOT NULL,
                   ADDRESS        CHAR(50),
                   SALARY         REAL);
            """
            cur.execute(sql)

            print("create table successfully")

            # 添加数据
            # 在1个conn.execute里面里面履行多个sql语句是非法的
            cur.executemany("INSERT INTO COMPANY (NAME,AGE,ADDRESS,SALARY) VALUES ( %s, %s, %s, %s )",
                            [('Paul', 32, 'California', 20000.00),
                             ('Allen', 25, 'Texas', 15000.00),
                             ('Teddy', 23, 'Norway', 20000.00),
                             ('Mark', 25, 'Rich-Mond ', 65000.00),
                             ('David', 27, 'Texas', 85000.00),
                             ('Kim', 22, 'South-Hall', 45000.00),
                             ('James', 24, 'Houston', 10000.00)])

            # 提交,否则重新运行程序时,表中无数据
            conn.commit()
            print("insert successfully")

            # 查询表
            sql = """
                select id,NAME,AGE,ADDRESS,SALARY FROM COMPANY
             """

            cur.execute(sql)

            for row in cur.fetchall():
                print("-" * 50)  # 输出50个-,作为分界限
                print("%⑴0s %s" % ("id", row[0]))  # 字段名固定10位宽度,并且左对齐
                print("%⑴0s %s" % ("name", row[1]))
                print("%⑴0s %s" % ("age", row[2]))
                print("%⑴0s %s" % ("address", row[3]))
                print("%⑴0s %s" % ("salary", row[4]))

except MySQLdb.Error as e:
    print("Mysql Error:", e)
    traceback.print_exc()  # 打印毛病栈信息

2.2 使用MySQLdb

#! /usr/bin/env python2.7
# coding=utf⑻
# Created by xiaosanyu at 16/5/30

# mysqldb 只支持python2.7
# http://mysql-python.sourceforge.net/

import MySQLdb
from contextlib import closing
import traceback

try:
    # 获得1个数据库连接
    with closing(MySQLdb.connect(host='localhost', user='root', passwd='root', db='test', port=3306,charset='utf8')) as conn:
        print("connect database successfully")
        with closing(conn.cursor()) as cur:
            # 删除表
            cur.execute("DROP TABLE IF EXISTS  COMPANY")
            # 创建表
            sql = """
                     CREATE TABLE IF NOT EXISTS COMPANY
                   (ID INTEGER  PRIMARY KEY NOT NULL  auto_increment,
                   NAME           TEXT    NOT NULL,
                   AGE            INT     NOT NULL,
                   ADDRESS        CHAR(50),
                   SALARY         REAL);
            """
            cur.execute(sql)

            print("create table successfully")

            # 添加数据
            # 在1个conn.execute里面里面履行多个sql语句是非法的
            cur.executemany("INSERT INTO COMPANY (NAME,AGE,ADDRESS,SALARY) VALUES ( %s, %s, %s, %s )",
                            [('Paul', 32, 'California', 20000.00),
                             ('Allen', 25, 'Texas', 15000.00),
                             ('Teddy', 23, 'Norway', 20000.00),
                             ('Mark', 25, 'Rich-Mond ', 65000.00),
                             ('David', 27, 'Texas', 85000.00),
                             ('Kim', 22, 'South-Hall', 45000.00),
                             ('James', 24, 'Houston', 10000.00)])

            # 提交,否则重新运行程序时,表中无数据
            conn.commit()
            print("insert successfully")

            # 查询表
            sql = """
                select id,NAME,AGE,ADDRESS,SALARY FROM COMPANY
             """

            cur.execute(sql)

            for row in cur.fetchall():
                print("-" * 50)  # 输出50个-,作为分界限
                print("%⑴0s %s" % ("id", row[0]))  # 字段名固定10位宽度,并且左对齐
                print("%⑴0s %s" % ("name", row[1]))
                print("%⑴0s %s" % ("age", row[2]))
                print("%⑴0s %s" % ("address", row[3]))
                print("%⑴0s %s" % ("salary", row[4]))

except MySQLdb.Error as e:
    print("Mysql Error:", e)
    traceback.print_exc()  # 打印毛病栈信息

2.3使用pymysql

2.1和2.2节使用MySQLdb，不支持Python3.x
pymysql对Python2.x和Python3.x的支持都比较好

# Created by xiaosanyu at 16/5/30
# coding=utf⑻

# https://github.com/PyMySQL/PyMySQL/
import pymysql
from contextlib import closing
import traceback

try:
    # 获得1个数据库连接,with关键字 表示退出时,conn自动关闭
    # with 嵌套上1层的with 要使用closing()
    with closing(pymysql.connect(host='localhost', user='root', passwd='root', db='test', port=3306,
                                 charset='utf8')) as conn:

        print("connect database successfully")

        # 获得游标,with关键字 表示退出时,cur自动关闭
        with conn.cursor() as cur:
            # 删除表
            cur.execute("DROP TABLE IF EXISTS  COMPANY")
            # 创建表
            sql = """
                     CREATE TABLE IF NOT EXISTS COMPANY
                   (ID INTEGER  PRIMARY KEY NOT NULL  auto_increment,
                   NAME           TEXT    NOT NULL,
                   AGE            INT     NOT NULL,
                   ADDRESS        CHAR(50),
                   SALARY         REAL);
            """
            cur.execute(sql)

            print("create table successfully")

            # 添加数据
            # 在1个conn.execute里面里面履行多个sql语句是非法的
            cur.executemany("INSERT INTO COMPANY (NAME,AGE,ADDRESS,SALARY) VALUES ( %s, %s, %s, %s )",
                            [('Paul', 32, 'California', 20000.00),
                             ('Allen', 25, 'Texas', 15000.00),
                             ('Teddy', 23, 'Norway', 20000.00),
                             ('Mark', 25, 'Rich-Mond ', 65000.00),
                             ('David', 27, 'Texas', 85000.00),
                             ('Kim', 22, 'South-Hall', 45000.00),
                             ('James', 24, 'Houston', 10000.00)])

            # 提交,否则重新运行程序时,表中无数据
            conn.commit()
            print("insert successfully")

            # 查询表
            sql = """
                select id,NAME,AGE,ADDRESS,SALARY FROM COMPANY
             """

            cur.execute(sql)

            for row in cur.fetchall():
                print("-" * 50)  # 输出50个-,作为分界限
                print("%⑴0s %s" % ("id", row[0]))  # 字段名固定10位宽度,并且左对齐
                print("%⑴0s %s" % ("name", row[1]))
                print("%⑴0s %s" % ("age", row[2]))
                print("%⑴0s %s" % ("address", row[3]))
                print("%⑴0s %s" % ("salary", row[4]))
except pymysql.Error as e:
    print("Mysql Error:", e)
    traceback.print_exc()

3.连接mssql

# Created by xiaosanyu at 16/5/30

# http://www.pymssql.org/en/latest/
import pymssql
from contextlib import closing

try:
    # 先要保证数据库中有test数据库
    # 获得1个数据库连接,with关键字 表示退出时,conn自动关闭
    # with 嵌套上1层的with 要使用closing()
    with closing(pymssql.connect(host='192.168.100.114', user='sa', password='sa12345', database='test', port=1433,
                                 charset='utf8')) as conn:

        print("connect database successfully")

        # 获得游标,with关键字 表示退出时,cur自动关闭
        with conn.cursor() as cur:
            # 删除表
            cur.execute(
                    '''if exists (select 1 from  sys.objects where name='COMPANY' and  type='U')  drop table COMPANY''')
            # 创建表
            sql = """
                     CREATE TABLE  COMPANY
                   (ID INT  IDENTITY(1,1) PRIMARY KEY NOT NULL ,
                   NAME           TEXT    NOT NULL,
                   AGE            INT     NOT NULL,
                   ADDRESS        CHAR(50),
                   SALARY         REAL);
            """
            cur.execute(sql)

            print("create table successfully")

            # 添加数据
            # 在1个conn.execute里面里面履行多个sql语句是非法的
            cur.executemany("INSERT INTO COMPANY (NAME,AGE,ADDRESS,SALARY) VALUES ( %s, %s, %s, %s )",
                            [('Paul', 32, 'California', 20000.00),
                             ('Allen', 25, 'Texas', 15000.00),
                             ('Teddy', 23, 'Norway', 20000.00),
                             ('Mark', 25, 'Rich-Mond', 65000.00),
                             ('David', 27, 'Texas', 85000.00),
                             ('Kim', 22, 'South-Hall', 45000.00),
                             ('James', 24, 'Houston', 10000.00)])

            # 提交,否则重新运行程序时,表中无数据
            conn.commit()
            print("insert successfully")

            # 查询表
            sql = """
                select id,NAME,AGE,ADDRESS,SALARY FROM COMPANY
             """

            cur.execute(sql)

            for row in cur.fetchall():
                print("-" * 50)  # 输出50个-,作为分界限
                print("%⑴0s %s" % ("id", row[0]))  # 字段名固定10位宽度,并且左对齐
                print("%⑴0s %s" % ("name", row[1]))
                print("%⑴0s %s" % ("age", row[2]))
                print("%⑴0s %s" % ("address", row[3]))
                print("%⑴0s %s" % ("salary", row[4]))
except pymssql.Error as e:
    print("mssql Error:", e)
    # traceback.print_exc()

4.连接MongoDB

# Created by xiaosanyu at 16/5/30

# https://docs.mongodb.com/ecosystem/drivers/python/
# https://pypi.python.org/pypi/pymongo/

import pymongo
from pymongo.mongo_client import MongoClient
import pymongo.errors
import traceback

try:
    # 连接到 mongodb 服务
    mongoClient = MongoClient('localhost', 27017)
    # 连接到数据库
    mongoDatabase = mongoClient.test
    print("connect database successfully")

    # 获得集合
    mongoCollection = mongoDatabase.COMPANY

    # 移除所有数据
    mongoCollection.remove()

    # 添加数据
    mongoCollection.insert_many([{"Name": "Paul", "Age": "32", "Address": "California", "Salary": "20000.00"},
                                 {"Name": "Allen", "Age": "25", "Address": "Texas", "Salary": "15000.00"},
                                 {"Name": "Teddy", "Age": "23", "Address": "Norway", "Salary": "20000.00"},
                                 {"Name": "Mark", "Age": "25", "Address": "Rich-Mond", "Salary": "65000.00"},
                                 {"Name": "David", "Age": "27", "Address": "Texas", "Salary": "85000.00"},
                                 {"Name": "Kim", "Age": "22", "Address": "South-Hall", "Salary": "45000.00"},
                                 {"Name": "James", "Age": "24", "Address": "Houston", "Salary": "10000.00"}, ])

    #获得集合中的值
    for row in mongoCollection.find():
        print("-" * 50)  # 输出50个-,作为分界限
        print("%-10s %s" % ("_id", row['_id']))  # 字段名固定10位宽度,并且左对齐
        print("%-10s %s" % ("name", row['Name']))
        print("%-10s %s" % ("age", row['Age']))
        print("%-10s %s" % ("address", row['Address']))
        print("%-10s %s" % ("salary", row['Salary']))

    print('\n\n\n')
    # 使id自增
    mongoCollection.remove()
    # 创建计数表
    mongoDatabase.counters.save({"_id": "people_id", "sequence_value": 0})
    # 创建存储进程
    mongoDatabase.system_js.getSequenceValue = '''function getSequenceValue(sequenceName){
            var sequenceDocument = db.counters.findAndModify({
                query: {_id: sequenceName},
                update: {$inc:{sequence_value: 1}},
                new:true
            });
            return sequenceDocument.sequence_value;
        }'''
    mongoCollection.insert_many(
            [{"_id": mongoDatabase.eval("getSequenceValue('people_id')"), "Name": "Paul", "Age": "32",
              "Address": "California", "Salary": "20000.00"},
             {"_id": mongoDatabase.eval("getSequenceValue('people_id')"), "Name": "Allen", "Age": "25",
              "Address": "Texas", "Salary": "15000.00"},
             {"_id": mongoDatabase.eval("getSequenceValue('people_id')"), "Name": "Teddy", "Age": "23",
              "Address": "Norway", "Salary": "20000.00"},
             {"_id": mongoDatabase.eval("getSequenceValue('people_id')"), "Name": "Mark", "Age": "25",
              "Address": "Rich-Mond", "Salary": "65000.00"},
             {"_id": mongoDatabase.eval("getSequenceValue('people_id')"), "Name": "David", "Age": "27",
              "Address": "Texas", "Salary": "85000.00"},
             {"_id": mongoDatabase.eval("getSequenceValue('people_id')"), "Name": "Kim", "Age": "22",
              "Address": "South-Hall", "Salary": "45000.00"},
             {"_id": mongoDatabase.eval("getSequenceValue('people_id')"), "Name": "James", "Age": "24",
              "Address": "Houston", "Salary": "10000.00"}, ])

    for row in mongoCollection.find():
        print("-" * 50)  # 输出50个-,作为分界限
        print("%-10s %s" % ("_id", int(row['_id'])))  # 字段名固定10位宽度,并且左对齐
        print("%-10s %s" % ("name", row['Name']))
        print("%-10s %s" % ("age", row['Age']))
        print("%-10s %s" % ("address", row['Address']))
        print("%-10s %s" % ("salary", row['Salary']))
except pymongo.errors.PyMongoError as e:
    print("mongo Error:", e)
    traceback.print_exc()

5.连接Redis

5.1使用redis

# coding=utf⑻
# Created by xiaosanyu at 16/5/31

# https://pypi.python.org/pypi/redis/2.10.5
# http://redis-py.readthedocs.io/en/latest/#
import redis

r = redis.Redis(host='localhost', port=6379, db=0, password="12345")
print("connect", r.ping())

# 看信息
info = r.info()
# or 查看部份信息
# info = r.info("Server")

# 输出信息
items = info.items()
for i, (key, value) in zip(range(len(items)), items):
    print("item %s----%s:%s" % (i, key, value))

# 删除键和对应的值
r.delete("company")

# 可以1次性push1条或多条数据
r.rpush("company", {"id": 1, "Name": "Paul", "Age": "32", "Address": "California", "Salary": "20000.00"},
        {"id": 2, "Name": "Allen", "Age": "25", "Address": "Texas", "Salary": "15000.00"},
        {"id": 3, "Name": "Teddy", "Age": "23", "Address": "Norway", "Salary": "20000.00"})
r.rpush("company", {"id": 4, "Name": "Mark", "Age": "25", "Address": "Rich-Mond", "Salary": "65000.00"})
r.rpush("company", {"id": 5, "Name": "David", "Age": "27", "Address": "Texas", "Salary": "85000.00"})
r.rpush("company", {"id": 6, "Name": "Kim", "Age": "22", "Address": "South-Hall", "Salary": "45000.00"})
r.rpush("company", {"id": 7, "Name": "James", "Age": "24", "Address": "Houston", "Salary": "10000.00"})

# eval用来将dict格式的字符串转换成dict
for row in map(lambda x: eval(x), r.lrange("company", 0, r.llen("company"))):
    print("-" * 50)  # 输出50个-,作为分界限
    print("%-10s %s" % ("_id", row['id']))  # 字段名固定10位宽度,并且左对齐
    print("%-10s %s" % ("name", row['Name']))
    print("%-10s %s" % ("age", row['Age']))
    print("%-10s %s" % ("address", row['Address']))
    print("%-10s %s" % ("salary", row['Salary']))

# 关闭当前连接
r.shutdown()

5.2使用pyredis

# Created by xiaosanyu at 16/5/30

# http://pyredis.readthedocs.io/en/latest/
import pyredis

r = pyredis.Client(host='localhost', port=6379, database=0, password="12345")
print("connect", r.ping().decode("utf⑻"))

# 看信息

# info = r.execute("info").decode()
# or 查看部份信息
info = r.execute("info", "Server").decode()

# 输出信息
print(info)

# 删除键和对应的值
r.delete("company")

# 可以1次性push1条或多条数据
r.rpush("company", '''{"id": 1, "Name": "Paul", "Age": "32", "Address": "California", "Salary": "20000.00"}''',
        '''{"id": 2, "Name": "Allen", "Age": "25", "Address": "Texas", "Salary": "15000.00"}''',
        '''{"id": 3, "Name": "Teddy", "Age": "23", "Address": "Norway", "Salary": "20000.00"}''')
r.rpush("company", '''{"id": 4, "Name": "Mark", "Age": "25", "Address": "Rich-Mond", "Salary": "65000.00"}''')
r.rpush("company", '''{"id": 5, "Name": "David", "Age": "27", "Address": "Texas", "Salary": "85000.00"}''')
r.rpush("company", '''{"id": 6, "Name": "Kim", "Age": "22", "Address": "South-Hall", "Salary": "45000.00"}''')
r.rpush("company", '''{"id": 7, "Name": "James", "Age": "24", "Address": "Houston", "Salary": "10000.00"}''')

# eval用来将dict格式的字符串转换成dict
for row in map(lambda x: eval(x), r.lrange("company", 0, r.llen("company"))):
    print("-" * 50)  # 输出50个-,作为分界限
    print("%⑴0s %s" % ("_id", row['id']))  # 字段名固定10位宽度,并且左对齐
    print("%⑴0s %s" % ("name", row['Name']))
    print("%⑴0s %s" % ("age", row['Age']))
    print("%⑴0s %s" % ("address", row['Address']))
    print("%⑴0s %s" % ("salary", row['Salary']))

# 关闭当前连接
r.close()

代码下载：python_connect_database

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