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数据迁移可使用“包管理器控制台”(PMC) 或 CLI。本文列出使用CLI数据迁移命令和一些问题及解决方案。
以下列出添加迁移文件、撤销迁移、更新到数据库、删除数据库基本方法。如需指定DbContext，则在语句后加 -c DbContext名 。如需查看帮助可在命令后加 -h 。
dotnet ef migrations add 迁移文件名
dotnet ef migrations remove
dotnet ef database update
注意不是删除数据更改，是删除数据库，慎用。
dotnet ef database drop
无法执行，因为找不到指定的命令或文件。
可能的原因包括: *你拼错了内置的 dotnet 命令。 *你打算执行 .NET Core 程序，但 dotnet-install 不存在。 *你打算运行全局工具，但在路径上找不到名称前缀为 dotnet 的可执行文件。解决：打开CMD，输入：
dotnet tool install -g dotnet-ef
The EF Core tools version '3.1.0' is older than that of the runtime '3.1.2'. Update the tools for the latest features and bug fixes.
解决：需要更新EF Core tools版本，CMD中执行：
dotnet tool update -g dotnet-ef
It was not possible to find any compatible framework version
The framework 'Microsoft.NETCore.App', version '3.1.2' was not found. - The following frameworks were found: 2.1.9 at [C:\Program Files\dotnet\shared\Microsoft.NETCore.App] 2.1.15 at [C:\Program Files\dotnet\shared\Microsoft.NETCore.App] 3.1.1 at [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]You can resolve the problem by installing the specified framework and/or SDK.
The specified framework can be found at:
- https://aka.ms/dotnet-core-applaunch?framework=Microsoft.NETCore.App&framework_version=3.1.2&arch=x64&rid=win10-x64解决：到最后提供的网址下载SDK安装
No database provider has been configured for this DbContext. A provider can be configured by overriding the DbContext.OnConfiguring method or by using AddDbContext on the application service provider. If AddDbContext is used, then also ensure that your DbContext type accepts a DbContextOptions<TContext> object in its constructor and passes it to the base constructor for DbContext.
解决：需要在网站目录执行
More than one DbContext was found. Specify which one to use. Use the '-Context' parameter for PowerShell commands and the '--context' parameter for dotnet commands.
解决：如果有多个DBContext，需要指定迁移哪个DBContext。如：
dotnet ef migrations add InitialCreate -c DBContext名称
Your target project 'Do.TmsApi' doesn't match your migrations assembly 'Do.Models'. Either change your target project or change your migrations assembly.
Change your migrations assembly by using DbContextOptionsBuilder. E.g. options.UseSqlServer(connection, b => b.MigrationsAssembly("Do.TmsApi")). By default, the migrations assembly is the assembly containing the DbContext.Change your target project to the migrations project by using the Package Manager Console's Default project drop-down list, or by executing "dotnet ef" from the directory containing the migrations project.解决：如果DBContext和启动程序不在一个程序集，需要指定要迁移的程序集。代码中添加要迁移的程序集名称：
options.UseSqlServer(connection, b => b.MigrationsAssembly("Do.TmsApi"))
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