python连接数据库

一、连接mysql

1、安装库PyMySQL

2、2种连接方式。

# 第一种

import pymysql

# 直接生成db对象
db = pymysql.connect(host = 'localhost',
                       port = 3306,
                       user = 'root',
                       password = '123',
                       db = 'mrsoft',
                       charset = 'utf8',
                       cursorclass = pymysql.cursors.DictCursor
                    )
cursor = db.cursor() # 创建游标

# 第二种

import pymysql

# 通过字典的方式创建db对象
dictoj = {
    'host': 'localhost',
    'port': 3306,
    'user': 'root',
    'password': '123',
    'db': 'mrsoft',
    'charset': 'utf8',
    'cursorclass': pymysql.cursors.DictCursor
}
db = pymysql.connect(**dictoj)

3、添加数据采用executemany()方法

# 添加数据 executemany(operation ,seq_of_params)
data = [
    ('三国演义','四大名著','100.23','2007-1-3'),
    ('水浒传','四大名著','120.12','2004-2-24'),
    ('红楼梦','四大名著','130.29','2003-4-21'),
    ('西游记','四大名著','140.37','2002-7-1'),
    ('java开发','专业书','50.67','2019-1-21'),
    ('php开发实战','专业书','80.19','2017-2-22')
]
try:
    cursor.executemany('insert into books(name,category,price,publish_time) values(%s,%s,%s,%s)', data)
    db.commit()
except:
    db.rollback()  # 错误时执行回滚操作

4、代码

import pymysql

"""
# 直接生成db对象
db = pymysql.connect(host = 'localhost',
                       port = 3306,
                       user = 'root',
                       password = '123',
                       db = 'mrsoft',
                       charset = 'utf8',
                       cursorclass = pymysql.cursors.DictCursor
                    )
"""

# 通过字典的方式创建db对象
dictoj = {
    'host': 'localhost',
    'port': 3306,
    'user': 'root',
    'password': '123',
    'db': 'mrsoft',
    'charset': 'utf8',
    'cursorclass': pymysql.cursors.DictCursor
}
db = pymysql.connect(**dictoj)
cursor = db.cursor() # 创建游标
cursor.execute('drop table if exists books') # 游标的execute()方法
sql = """
create table books (
    id int(8) not null auto_increment,
    name varchar(50) not null,
    category varchar(50) not null,
    price decimal(10,2) default null,
    publish_time date default null,
    primary key (id)
) engine=myisam auto_increment=1 default charset= utf8;
"""
cursor.execute(sql)  # 执行sql

# 添加数据 executemany(operation ,seq_of_params)
data = [
    ('三国演义','四大名著','100.23','2007-1-3'),
    ('水浒传','四大名著','120.12','2004-2-24'),
    ('红楼梦','四大名著','130.29','2003-4-21'),
    ('西游记','四大名著','140.37','2002-7-1'),
    ('java开发','专业书','50.67','2019-1-21'),
    ('php开发实战','专业书','80.19','2017-2-22')
]
try:
    cursor.executemany('insert into books(name,category,price,publish_time) values(%s,%s,%s,%s)', data)
    db.commit()
except:
    db.rollback()  # 错误时执行回滚操作

db.close()

　　

二、连接SQL

1、引入库pymssql

2、连接

def conn():
    connect = pymssql.connect('.','sa','123','dbtest')
    if connect :
        print('connect success!')
        return connect
    else:
        print('connect failed!')

 3、数据库操作（新建表sql_test，插入数据，查询数据）

 注意插入数据后得commit提交下否则表中没有数据。

import pymssql

def conn():
    connect = pymssql.connect('.','sa','123','dbtest')
    if connect :
        print('connect success!')
        return connect
    else:
        print('connect failed!')

def createsql():
    cursor.execute('create table sql_test(id varchar(20),name varchar(50) default  null,sex bit not null)')
    db.commit()
    print('create success！')

def inssql():
    sql = "insert into sql_test(id,name,sex) values('1001','张三','0'),('1001','张三','0')"
    print('insert success!')
    return sql

def selectsql():
    sl = 'select id, name, sex from sql_test'
    return  sl

if __name__ == '__main__':
    db  = conn()  # 创建数据库对象
    cursor = db.cursor() # 创建游标
    createsql()  # 创建
    # 插入
    s0 = inssql()
    cursor.execute(s0)
    db.commit() # 插入以后必须得提交，否则没有数据
    # 查询
    s1 = selectsql()
    cursor.execute(s1)
    # 读取查询结果
    row = cursor.fetchone()
    while row :
        print("Id =%s,Name=%s,Sex =%s" % (row[0],row[1],row[2]))
        row = cursor.fetchone()
    cursor.close()
    db.close()