python连接MySQL数据库(pymysql的基本用法)

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导包:

    import pymysql

连接数据库:

 connection = pymysql.connect(#链接数据库
 host='localhost',
 user='root',
 password='********',
 db='studentsdb', #库名
 )

增删改查:

def find_data():
    cursor = connection.cursor()  # 创建游标.
    # SQL语句
    sql = 'select * from tb_user'
    # execute执行操作
    cursor.execute(sql)
    result = cursor.fetchall()
    print(type(result), cursor.rowcount)
    print(result)
    for i in result:
        print(i)
    cursor.close()
 
def add_data():
    cursor = connection.cursor()  # 创建游标.
    # 插入SQL语句
    sql = 'insert into tb_user(url,username,password) values (%s,%s,%s)'
    # 插入数据
    data = [
        ('123', '刘博蛋', '54238'),
        ('321', '王成杰', '54238'),
    ]
    #print(type(data[0]))
    # 拼接并执行SQL语句
    cursor.executemany(sql, data)
    # 涉及写操作要提交
    connection.commit()
    #print(cursor.rowcount)
    cursor.close()
 
def delete():
    cursor = connection.cursor()  # 创建游标.
    # 删除SQL语句
    sql = 'delete from tb_user where url = "123"'
    cursor.execute(sql)
    connection.commit()
    print(cursor.rowcount)
    cursor.close()
 
 
def update():
    cursor = connection.cursor()  # 创建游标.
    # 修改SQL语句
    sql = 'update tb_user set url="12345622" where password="123"'
    # 执行SQL语句
    cursor.execute(sql)
    connection.commit()
   # print(cursor.rowcount)
    cursor.close()

另外,需要注意的是在关闭数据库连接前要先关闭游标.