mysql.connector.errors.NotSupportedError: Authentication plugin ‘caching_sha2_password’ is not supported

出现该原因的问题是mysql8.0后加密方式改变了。

import mysql.connector
connection = mysql.connector.connect(
    host="localhost",
    user="root",
    passwd="password"
)
print(connection)

不支持身份验证插件“ caching_sha2_password”，

import mysql.connector

connection = mysql.connector.connect(
	host="localhost",
    user="root",
    passwd="password",
    auth_plugin='mysql_native_password'
)

print(connection)

TypeError: ‘module’ object is not callable

class User(object):
    def __init__(self, username, password):
        self.__username = username
        self.__password = password

    def getUserName(self):
        return self.__username

    def setUserName(self, username):
        self.__username = username
        return None

    def getPassword(self):
        return self.__password

    def serPassword(self, password):
        self.__password = password
        return None

import mysqlTest.User


if __name__ == "__main__":
    user = mysqlTest.User('zhangsan', 123456)
    print(user.getUserName())
    print(user.getPassword())

Python导入模块的方法有两种：

import module和 from module import区别是前者是导入包的模块即包下的py文件，后者是深入模块即可以导入py文件定义的类和方法。

# 将import改为from...import深入内部
from mysqlTest.User import User

mysql.connector.errors.ProgrammingError: Not all parameters were used in the SQL statement

def method():
    cursor.execute('insert into user(username,password) values(%s,%d)',("zhansan1","123456"))
    values = cursor.rowcount

    print(values)

    cursor.close()
    try:
        #num = 5 / 0
        conn.commit()
    except Exception:
        conn.rollback()
    finally:
        conn.close

cursor的sql语句中使用了python%d占位符。以上代码会执行出错，因为无论是数字（包括整数和浮点数）、字符串、日期时间或其他任意类型，都应该使用%s占位符。

Duplicate entry ‘zhangsan’ for key ‘username’

出现该错的原因是username字段设置了unique键，表示该键不可重复，所以插入重复的键是会报错。解决方法，删除unique键drop index username on table_name

sqlalchemy.orm.exc.FlushError: Instance <User at 0x3a8e7a8> has a NULL identity key

出现该错误的原因是：id是字符串类型，无法自增长

# 定义User对象:
class User(Base):
    # 表的名字:
    __tablename__ = 'user'

    # 表的结构:
    id = Column(String(20), primary_key=True)
    username = Column(String(20))
    password = Column(String(11))

    def __init__(self, username, password):
        self.username = username
        self.password = password