解决办法：
1、输入命令 mysql -u root -p 连接mysql
C:\mysql-8.0.19-winx64\bin>mysql -u root -p
Enter password: ***********
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 9
Server version: 8.0.19 MySQL Community Server - GPL
Copyright (c) 2000, 2020, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
owners.
Type ‘help;‘ or ‘\h‘ for help. Type ‘\c‘ to clear the current input statement.
2、输入以下命令 更改密码验证方式
mysql> alter user ‘root‘@‘localhost‘ identified with mysql_native_password by ‘数据库密码‘;
Query OK, 0 rows affected (0.10 sec)
3、打开mysql安装目录下的 my.ini，在[mysqld]下面添加代码：
default_authentication_plugin=mysql_native_password
------------------------my.ini-------------------------------
[Client]
port = 3306
default-character-set=utf8
[mysqld]
port = 3306
basedir=C:\mysql-8.0.19-winx64
datadir=C:\mysql-8.0.19-winx64\data
max_connections=200
character-set-server=utf8
default-storage-engine=INNODB
default_authentication_plugin=mysql_native_password
[mysql]
default-character-set=utf8
-------------------------------------------------------
4、重启mysql服务
C:\mysql-8.0.19-winx64\bin>net stop mysql
mysql 服务正在停止.
mysql 服务已成功停止。
C:\mysql-8.0.19-winx64\bin>net start mysql
mysql 服务正在启动 ..
mysql 服务已经启动成功。
ADO.Net实体数据模型添加DB-First/Code First报错
原文：https://www.cnblogs.com/pzxnet/p/12377057.html