PyCharm连接MySQL数据库，进行创建数据库实例的创建和表的创建以及表的增删改查操作

一、创建数据库实例

from pymysql import *
# 创建数据库实例
#1.建立数据库连接
conn  = connect(host="192.168.20.101",user="root",password="123456")
# 2.获取游标对象
mycur = conn.cursor()
#3.执行创建数据库实例，并返回int类型结果   1表示添加成功，如果数据库实例已经存在则抛出异常
try:
    result = mycur.execute("create database pydb")
    print("添加数据库实例后返回的结果：",result)
except ProgrammingError as msg:
    print("添加数据库实例出现异常：",msg)
finally:
    #4.关闭游标
    mycur.close()
    # 5.关闭连接
    conn.close()

二、创建表

from pymysql import *
# 1. 创建数据库连接对象
conn = connect(host="192.168.20.101", user="root", password="123456",database="pydb")
# 2.从连接对象上获取游标
mycur = conn.cursor()
# 3.执行创建数据库的表tb_user,返回int类型的结果  成功添加表的话，返回0 ；添加失败抛出异常
try:
    result = mycur.execute("""
    CREATE TABLE `tb_user` (
      `id` bigint(20) NOT NULL AUTO_INCREMENT,
      `username` varchar(50) NOT NULL COMMENT '用户名',
      `password` varchar(32) NOT NULL COMMENT '密码，加密存储',
      `phone` varchar(20) DEFAULT NULL COMMENT '注册手机号',
      `email` varchar(50) DEFAULT NULL COMMENT '注册邮箱',
      `created` datetime NOT NULL,
      `updated` datetime NOT NULL,
      PRIMARY KEY (`id`),
      UNIQUE KEY `username` (`username`) USING BTREE,
      UNIQUE KEY `phone` (`phone`) USING BTREE,
      UNIQUE KEY `email` (`email`) USING BTREE
    ) ENGINE=InnoDB AUTO_INCREMENT=37 DEFAULT CHARSET=utf8 COMMENT='用户表'
    """)
    print("返回结果：%d"%result)
except (InternalError,ProgrammingError) as msg:
    print("表添加出现异常，异常信息：%s"%msg)
finally:
    # 4关闭游标
    mycur.close()
    # 5 关闭连接
    conn.close()

三、向表中插入数据

from pymysql import  *
# 1.建立到数据库连接
conn = connect(host="192.168.20.101",user="root",password="123456",database="pydb")
# 2.获取游标
mycur = conn.cursor()
try:
    # 3.开启事务
    conn.begin()
    # 4.执行插入数据，并返回影响的行数
    rowNum1 = mycur.execute("""insert into `tb_user` values(1,'lisi','e10adc3949ba59abbe56e057f20f883e','13412345678','[e-mail]','2020-12-25 17:03:55','2020-12-25 17:03:55');""")
    # 防止sql注入的风险，通过%s占位符，
    rowNum2 = mycur.execute("""insert into `tb_user` values(%s,%s,%s,%s,%s,%s,%s);""",
                            (2,'wangwu','202cb962ac59075b964b07152d234b70','13412345679','[e-mail]','2020-12-26 17:03:55','2020-12-26 17:03:55'))
    # 在表名后添加列名
    rowNum3 = mycur.execute("""insert into tb_user(username,password,phone,email,created,updated) values(%s,%s,%s,%s,%s,%s);""",
                            ('zhaoliu','e10adc3949ba59abbe56e057f20f883e','13412345675','[e-mail]','2020-12-27 17:03:55','2020-12-27 17:03:55'))
    row = rowNum1+rowNum2+rowNum3
    print("受影响的行数：",row)
    if row==3:
        #提交事务
        conn.commit()
    else:
        # 回滚事务
        conn.rollback()
except IntegrityError as msg:
    print("出现异常",msg)
    # 回滚事务
    conn.rollback()
finally:
    # 关闭游标
    mycur.close()
    # 关闭连接
    conn.close()

四、查询表中数据

from pymysql import *
# 建立连接
conn = connect(host="192.168.20.101",user="root",password="123456",database="pydb")
# 获取游标
mycur = conn.cursor()
# 执行查询,并返回查询出来的数据的总行数
rowNum = mycur.execute("select * from tb_user")
print("共查询出 %d 行数据"%rowNum)
# 获取查询出来的数据
results = mycur.fetchall()
print(type(results))
#遍历输出
for result in results:
    # print(result)
    print(result[0],result[1])

#关闭游标和连接
mycur.close()
conn.close()

五、修改表中数据

from pymysql import *
conn = connect(host="192.168.20.101",user="root",password="123456",database="pydb")
mycur = conn.cursor()
try:
    conn.begin()
    row = mycur.execute("update tb_user set username=%s,phone=%s,email=%s,updated=%s where id = %s",
                        ('zhaomin','13888889999','[e-mail]','2021-01-29 20:16:20',37))
    # 提交事务
    conn.commit()
    if row ==1:
        print("修改成功")
    else:
        print("修改失败")
except Exception as msg:
    #回滚事务
    conn.rollback()
    print("修改失败，提示信息：",msg)
finally:
    # 关闭游标
    mycur.close()
    # 关闭数据库连接
    conn.close()

六、删除表中数据

from pymysql import *
# 建立数据库连接
conn = connect(host="192.168.20.101",user="root",password="123456",database="pydb")
# 获取游标
mycur = conn.cursor()
try:
    # 开启事务
    conn.begin()
    # 执行删除数据
    rowNum = mycur.execute("delete from tb_user where id = %s",(37,))
    print("受影响的行数:",rowNum)
    conn.commit()
except Exception as msg:
    print("删除抛出异常，提示信息:",msg)
    conn.rollback()#回滚事务
finally:
    # 关闭游标和数据库连接
    mycur.close()
    conn.close()