Python pymysql

Posted 2022-10-01 风流 少年

一：安装mysql库

pip install pymysql

二：基础示例

import pymysql
from pymysql.cursors import DictCursor
# 1.创建连接
# cursorclass: 全局定义，表示查询时是返回的数据类型，字典还是元组(默认)
conn = pymysql.connect(host='127.0.0.1',
                       port=3306,
                       user='root',
                       password='123456',
                       database='test',
                       charset='utf8',
                       cursorclass=DictCursor)

# 2.获取游标，局部定义cursor
cursor = conn.cursor(cursor=pymysql.cursors.DictCursor)

# 3.定义sql，最好使用"""来定义字符串，这样关键字会变色
create_table_sql = """
CREATE TABLE IF NOT EXISTS sys_user2 (
  `id` bigint(20) unsigned NOT NULL AUTO_INCREMENT,
  `username` varchar(15) NOT NULL COMMENT '用户名',
  `gender` tinyint(3) unsigned DEFAULT '0' COMMENT '性别(0: 女 1：男)',
  `amount` decimal(10,2) DEFAULT NULL,
  `create_time` datetime DEFAULT CURRENT_TIMESTAMP COMMENT '注册时间',
  PRIMARY KEY (`id`),
  UNIQUE KEY `uk` (`username`) USING BTREE
) ENGINE=InnoDB AUTO_INCREMENT=1 DEFAULT CHARSET=utf8
"""
# 4.执行
cursor.execute(create_table_sql)

delete_sql = """
delete from sys_user2
"""
cursor.execute(delete_sql)

insert_sql = """
insert into sys_user2(username, gender, amount, create_time) values(%s, %s, %s, now())
"""
# 插入1条
cursor.execute(insert_sql, ['monday', 0, 9999999])
# 插入多条
cursor.executemany(insert_sql, [('test', 0, 9999999), ('modely', 0, 66666666)])

update_sql = """
update sys_user2 set amount = %s where username = %s
"""
cursor.execute(update_sql, ['88888888', 'modely'])

# 注意：先查询再获取数据，不像其它语言一样直接返回结果
select_sql = """
select * from sys_user2
"""
cursor.execute(select_sql)
fetchone = cursor.fetchone()
fetchmany = cursor.fetchmany(2)
# 注意：总共有三条，上面游标已经走到最后了，所以下面游标再走就没有数据了
fetchall = cursor.fetchall()

# insert, update, delete 操作都需要显式提交
conn.commit()
# conn.rollback()

# 5.关闭游标
cursor.close()

# 关闭连接
conn.close()