dotnet 3.1 之后，需要升级 dotnet ef命令
dotnet tool install --global dotnet-ef
命令使用帮助 dotnet ef dbcontext scaffold -h
Arguments: 参数： The connection string to the database. 数据库连接字符串 The provider to use. (E.g. Microsoft.EntityFrameworkCore.SqlServer) 提供程序类型
Options: 其他选项： -d|–data-annotations Use attributes to configure the model (where possible). If omitted, only the fluent API is used. 数据注释使用属性来配置模型（如果可能）。如果省略，则只使用fluent API。
-c|–context The name of the DbContext. DbContext 的名称
–context-dir The directory to put DbContext file in. Paths are relative to the project directory. DbContext 的路径
-f|–force Overwrite existing files. 覆盖已经存在的文件
-o|–output-dir The directory to put files in. Paths are relative to the project directory. 输出目录
–schema <SCHEMA_NAME>… The schemas of tables to generate entity types for. 要为其生成实体类型的表的架构。
-t|–table <TABLE_NAME>… The tables to generate entity types for. 要生成实体代码的表的名称 支持视图名称 多个table用多个-t
–use-database-names Use table and column names directly from the database. 使用数据库名称
–json Show JSON output. 输出内容，以json显示
-p|–project The project to use. 项目名称
-s|–startup-project The startup project to use. 开始项目名称（不太明白）
–framework The target framework. framework的版本
–configuration The configuration to use. 配置信息
–runtime <RUNTIME_IDENTIFIER> The runtime to use. 运行版本（？？）
–msbuildprojectextensionspath The MSBuild project extensions path. Defaults to “obj”. –no-build Don’t build the project. Only use this when the build is up-to-date. -h|–help Show help information -v|–verbose Show verbose output. –no-color Don’t colorize output. –prefix-output Prefix output with level.
sql server--------------------------------------------------------------- dotnet ef dbcontext scaffold “Server=(local);Database=lun;User ID=sa;Password=;” Microsoft.EntityFrameworkCore.SqlServer -o models -c Lun_DbContext
my sql--------------------------------------------------------------- Scaffold-DbContext “server=127.0.0.1;uid=root;pwd=1234123;database=shop” Pomelo.EntityFrameworkCore.Mysql -f -o Shop/Models
