原文:ASP.NET Core Identity 迁移数据 - ASP.NET Core 基础教程 - 简单教程，简单编程
ASP.NET Core Identity 迁移数据
上一章节中我们配置了 Identity ，也让我们的应用程序正常运行起来了，在访问未授权页面的时候会跳转到 /Accout/Login 页面。接下来我们就要实现登录的功能
但是，咦，好像还没创建用户表呢..哎呀，不是没创建用户表，而是没做 Identity 的数据迁移
那么，本章节接下来的内容，就开始迁移 Identity 数据呗
数据库连接配置
对了，我在看官方文档的过程中，发现了两种配置数据库连接的方法
一、第一种是在 Startup 类中的 ConfigureServices 方法中配置
services.AddEntityFrameworkSqlite().AddDbContext<HelloWorldDBContext>(options => options.UseSqlite(Configuration["database:connection"]));
这种方法需要我们的 HelloWorldDBContext 有一个可以接受 DbContextOptions<HelloWorldDBContext> 类型参数的构造函数
public HelloWorldDBContext(DbContextOptions<HelloWorldDBContext> options)
: base(options)
{
}
二、第二种方法只需要在 HelloWorldDBContext 类中重写方法 OnConfiguring
protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder) { optionsBuilder.UseSqlite("Data Source=blogging.db"); }
然后在 Startup 类中的 ConfigureServices 方法种就可以这么写了
services.AddEntityFrameworkSqlite().AddDbContext<HelloWorldDBContext>();
看起来是不是第二种更简单更方便更简洁
后知后觉，醉了，这次，我们就使用这种方法吧，然后将其它相关的都统统删掉
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首先删除
Startup类中的ConfigureServices方法中的相关配置public void ConfigureServices(IServiceCollection services) { services.AddMvc(); services.AddEntityFrameworkSqlite().AddDbContext<HelloWorldDBContext>(); services.AddIdentity<User, IdentityRole>().AddEntityFrameworkStores<HelloWorldDBContext>(); } -
其次在
HelloWorldDBContext类中重写方法OnConfiguring，且删除带参数的构造函数其实删除了带参数的构造函数，那么不带参数的构造函数也可以删除了，于是就变成了
using System; using Microsoft.EntityFrameworkCore; using Microsoft.AspNetCore.Identity.EntityFrameworkCore; using Microsoft.Extensions.Configuration; namespace HelloWorld.Models { public class HelloWorldDBContext:IdentityDbContext<User> { public DbSet<Employee> Employees { get; set; } protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder) { optionsBuilder.UseSqlite("Data Source=blogging.db"); } } }这种方法我还没找到如何引用 Configuration 属性的方式，如果你知道，请麻烦告诉我下
重启下我们的应用程序，刷新下首页，看看是否正常输出
最佳实战
实际应用中，你千万不要像我这么激进，因为这两种方式是互补的关系，也就是说 OnConfiguring() 方法可以覆写传递给 HelloWorldDBContext(DbContextOptions<HelloWorldDBContext> options) 的连接
当一个应用需要连接多个数据库的时候，结合这两种方式非常有用，第一种方式用于默认的数据库，第二种方式用于特定的数据库
迁移 Identity 数据
好了，让我门言归正传吧，开始迁移 Identity 数据。其实前面的 EF 框架中我们已经迁移过一次了，不知道大家是否还记得如何迁移呢
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首先停止我们的应用程序，不然会报错，因为我们使用的是文件系统数据库
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其次打开 控制台窗口 ( 终端或 Power Shell 或 命令提示符 )，定位到我们的
HelloWorld项目下$ cd ~/Developer/aspnetcore/HelloWorld/HelloWorld我用的是 macOS，且我的 HelloWorld 保存在
~/Developer/aspnetcore/HelloWorld/HelloWorld然后使用
ls命名就可以列出当前目录下的所有文件和子目录$ ls AppSettings.json Controllers HelloWorld.csproj Models Program.cs Properties Startup.cs Views bin obj wwwroot
如果你使用的是 Windows，且使用的不是 Power Shell，那么你应该使用
dir命令而不是ls命令如果能看到
HelloWorld.csproj则说明处于正确的目录，否则你应该继续cd到该目录下 -
然后可以运行下列命令创建迁移代码
dotnet ef migrations add InitialIdentity -v
参数 说明 dotnet 是 .NET 框架所有命令的开始标识 ef 是指使用 Entity Framework 提供的命令 migrations 是指使用迁移命令 add 是指添加迁移 InitialCreate 是本次迁移的说明，你可以改成任意文本，但我们推荐最好是能清楚的描述本次迁移的意图 -v 参数用于输出创建迁移代码时的运行日志，方便出错时我们可以查看错在哪里 运行结果如下
$ dotnet ef migrations add InitialIdentity -v Using project '/Users/yufei/Developer/aspnetcore/HelloWorld/HelloWorld/HelloWorld.csproj'. Using startup project '/Users/yufei/Developer/aspnetcore/HelloWorld/HelloWorld/HelloWorld.csproj'. Writing '/Users/yufei/Developer/aspnetcore/HelloWorld/HelloWorld/obj/HelloWorld.csproj.EntityFrameworkCore.targets'... dotnet msbuild /target:GetEFProjectMetadata /property:EFProjectMetadataFile=/var/folders/yk/2446sljj6hn82nvzkdgxltmw0000gn/T/tmpbjHVNk.tmp /verbosity:quiet /nologo /Users/yufei/Developer/aspnetcore/HelloWorld/HelloWorld/HelloWorld.csproj Writing '/Users/yufei/Developer/aspnetcore/HelloWorld/HelloWorld/obj/HelloWorld.csproj.EntityFrameworkCore.targets'... dotnet msbuild /target:GetEFProjectMetadata /property:EFProjectMetadataFile=/var/folders/yk/2446sljj6hn82nvzkdgxltmw0000gn/T/tmpDgtTNf.tmp /verbosity:quiet /nologo /Users/yufei/Developer/aspnetcore/HelloWorld/HelloWorld/HelloWorld.csproj dotnet build /Users/yufei/Developer/aspnetcore/HelloWorld/HelloWorld/HelloWorld.csproj /verbosity:quiet /nologo Build succeeded. 0 Warning(s) 0 Error(s) Time Elapsed 00:00:03.64 dotnet exec --depsfile /Users/yufei/Developer/aspnetcore/HelloWorld/HelloWorld/bin/Debug/netcoreapp2.1/HelloWorld.deps.json --additionalprobingpath /Users/yufei/.nuget/packages --additionalprobingpath /usr/local/share/dotnet/sdk/NuGetFallbackFolder --runtimeconfig /Users/yufei/Developer/aspnetcore/HelloWorld/HelloWorld/bin/Debug/netcoreapp2.1/HelloWorld.runtimeconfig.json /usr/local/share/dotnet/sdk/2.1.301/DotnetTools/dotnet-ef/2.1.1/tools/netcoreapp2.1/any/tools/netcoreapp2.0/any/ef.dll migrations add InitialIdentity --assembly /Users/yufei/Developer/aspnetcore/HelloWorld/HelloWorld/bin/Debug/netcoreapp2.1/HelloWorld.dll --startup-assembly /Users/yufei/Developer/aspnetcore/HelloWorld/HelloWorld/bin/Debug/netcoreapp2.1/HelloWorld.dll --project-dir /Users/yufei/Developer/aspnetcore/HelloWorld/HelloWorld/ --language C# --working-dir /Users/yufei/Developer/aspnetcore/HelloWorld/HelloWorld --verbose --root-namespace HelloWorld Using assembly 'HelloWorld'. Using startup assembly 'HelloWorld'. Using application base '/Users/yufei/Developer/aspnetcore/HelloWorld/HelloWorld/bin/Debug/netcoreapp2.1'. Using working directory '/Users/yufei/Developer/aspnetcore/HelloWorld/HelloWorld'. Using root namespace 'HelloWorld'. Using project directory '/Users/yufei/Developer/aspnetcore/HelloWorld/HelloWorld/'. Finding DbContext classes... Finding IDesignTimeDbContextFactory implementations... Finding application service provider... Finding IWebHost accessor... Using environment 'Development'. Using application service provider from IWebHost accessor on 'Program'. Found DbContext 'HelloWorldDBContext'. Finding DbContext classes in the project... Using context 'HelloWorldDBContext'. Finding design-time services for provider 'Microsoft.EntityFrameworkCore.Sqlite'... Using design-time services from provider 'Microsoft.EntityFrameworkCore.Sqlite'. Finding design-time services referenced by assembly 'HelloWorld'. No referenced design-time services were found. Finding IDesignTimeServices implementations in assembly 'HelloWorld'... No design-time services were found. DetectChanges starting for 'HelloWorldDBContext'. DetectChanges completed for 'HelloWorldDBContext'. DetectChanges starting for 'HelloWorldDBContext'. DetectChanges completed for 'HelloWorldDBContext'. DetectChanges starting for 'HelloWorldDBContext'. DetectChanges completed for 'HelloWorldDBContext'. DetectChanges starting for 'HelloWorldDBContext'. DetectChanges completed for 'HelloWorldDBContext'. Writing migration to '/Users/yufei/Developer/aspnetcore/HelloWorld/HelloWorld/Migrations/20180624040354_InitialIdentity.cs'. Writing model snapshot to '/Users/yufei/Developer/aspnetcore/HelloWorld/HelloWorld/Migrations/HelloWorldDBContextModelSnapshot.cs'. 'HelloWorldDBContext' disposed. Done. To undo this action, use 'ef migrations remove'大概意思就是经过漫长的岁月，成功创建了迁移代码
这一步非常容易出错，如果你有任何错误，欢迎你在讨论区留下你包括的意见
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创建迁移成功后，我们就可以使用下面的命令查看当前有多少迁移代码和它们的状态
$ dotnet ef migrations list
运行结果如下
$ dotnet ef migrations list 20180623011249_InitialCreate 20180624040354_InitialIdentity
可以看到总共有两个迁移代码，下面那个
20180624040354_InitialIdentity就是我们刚刚创建在解决方案管理器中我们还可以看到
Migrations又多了很多文件
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接下来我们就要开始应用这些迁移来更新数据库，执行下面的命令来应用迁移代码
$ dotnet ef database update -v
参数 说明 dotnet 是 .NET 框架所有命令的开始标识 ef 是指使用 Entity Framework 提供的命令 database 是指使用数据库相关命令 update 是指更新数据库 -v 参数用于输出创建迁移代码时的运行日志，方便出错时我们可以查看错在哪里 执行以上命令，输出结果如下
$ dotnet ef database update -v Using project '/Users/yufei/Developer/aspnetcore/HelloWorld/HelloWorld/HelloWorld.csproj'. Using startup project '/Users/yufei/Developer/aspnetcore/HelloWorld/HelloWorld/HelloWorld.csproj'. Writing '/Users/yufei/Developer/aspnetcore/HelloWorld/HelloWorld/obj/HelloWorld.csproj.EntityFrameworkCore.targets'... dotnet msbuild /target:GetEFProjectMetadata /property:EFProjectMetadataFile=/var/folders/yk/2446sljj6hn82nvzkdgxltmw0000gn/T/tmp6jVQsB.tmp /verbosity:quiet /nologo /Users/yufei/Developer/aspnetcore/HelloWorld/HelloWorld/HelloWorld.csproj Writing '/Users/yufei/Developer/aspnetcore/HelloWorld/HelloWorld/obj/HelloWorld.csproj.EntityFrameworkCore.targets'... dotnet msbuild /target:GetEFProjectMetadata /property:EFProjectMetadataFile=/var/folders/yk/2446sljj6hn82nvzkdgxltmw0000gn/T/tmpXNRfCA.tmp /verbosity:quiet /nologo /Users/yufei/Developer/aspnetcore/HelloWorld/HelloWorld/HelloWorld.csproj dotnet build /Users/yufei/Developer/aspnetcore/HelloWorld/HelloWorld/HelloWorld.csproj /verbosity:quiet /nologo Build succeeded. 0 Warning(s) 0 Error(s) Time Elapsed 00:00:04.59 dotnet exec --depsfile /Users/yufei/Developer/aspnetcore/HelloWorld/HelloWorld/bin/Debug/netcoreapp2.1/HelloWorld.deps.json --additionalprobingpath /Users/yufei/.nuget/packages --additionalprobingpath /usr/local/share/dotnet/sdk/NuGetFallbackFolder --runtimeconfig /Users/yufei/Developer/aspnetcore/HelloWorld/HelloWorld/bin/Debug/netcoreapp2.1/HelloWorld.runtimeconfig.json /usr/local/share/dotnet/sdk/2.1.301/DotnetTools/dotnet-ef/2.1.1/tools/netcoreapp2.1/any/tools/netcoreapp2.0/any/ef.dll database update --assembly /Users/yufei/Developer/aspnetcore/HelloWorld/HelloWorld/bin/Debug/netcoreapp2.1/HelloWorld.dll --startup-assembly /Users/yufei/Developer/aspnetcore/HelloWorld/HelloWorld/bin/Debug/netcoreapp2.1/HelloWorld.dll --project-dir /Users/yufei/Developer/aspnetcore/HelloWorld/HelloWorld/ --language C# --working-dir /Users/yufei/Developer/aspnetcore/HelloWorld/HelloWorld --verbose --root-namespace HelloWorld Using assembly 'HelloWorld'. Using startup assembly 'HelloWorld'. Using application base '/Users/yufei/Developer/aspnetcore/HelloWorld/HelloWorld/bin/Debug/netcoreapp2.1'. Using working directory '/Users/yufei/Developer/aspnetcore/HelloWorld/HelloWorld'. Using root namespace 'HelloWorld'. Using project directory '/Users/yufei/Developer/aspnetcore/HelloWorld/HelloWorld/'. Finding DbContext classes... Finding IDesignTimeDbContextFactory implementations... Finding application service provider... Finding IWebHost accessor... Using environment 'Development'. Using application service provider from IWebHost accessor on 'Program'. Found DbContext 'HelloWorldDBContext'. Finding DbContext classes in the project... Using context 'HelloWorldDBContext'. Finding design-time services for provider 'Microsoft.EntityFrameworkCore.Sqlite'... Using design-time services from provider 'Microsoft.EntityFrameworkCore.Sqlite'. Finding design-time services referenced by assembly 'HelloWorld'. No referenced design-time services were found. Finding IDesignTimeServices implementations in assembly 'HelloWorld'... No design-time services were found. Migrating using database 'main' on server 'blogging.db'. Opening connection to database 'main' on server 'blogging.db'. Opened connection to database 'main' on server '/Users/yufei/Developer/aspnetcore/HelloWorld/HelloWorld/blogging.db'. Executing DbCommand [Parameters=[], CommandType='Text', CommandTimeout='30'] PRAGMA foreign_keys=ON; Executed DbCommand (33ms) [Parameters=[], CommandType='Text', CommandTimeout='30'] PRAGMA foreign_keys=ON; Opening connection to database 'main' on server 'blogging.db'. Opened connection to database 'main' on server '/Users/yufei/Developer/aspnetcore/HelloWorld/HelloWorld/blogging.db'. Executing DbCommand [Parameters=[], CommandType='Text', CommandTimeout='30'] PRAGMA foreign_keys=ON; Executed DbCommand (0ms) [Parameters=[], CommandType='Text', CommandTimeout='30'] PRAGMA foreign_keys=ON; Executing DbCommand [Parameters=[], CommandType='Text', CommandTimeout='30'] SELECT COUNT(*) FROM "sqlite_master" WHERE "name" = '__EFMigrationsHistory' AND "type" = 'table'; Executed DbCommand (9ms) [Parameters=[], CommandType='Text', CommandTimeout='30'] SELECT COUNT(*) FROM "sqlite_master" WHERE "name" = '__EFMigrationsHistory' AND "type" = 'table'; Closing connection to database 'main' on server '/Users/yufei/Developer/aspnetcore/HelloWorld/HelloWorld/blogging.db'. Closed connection to database 'main' on server 'blogging.db'. Opening connection to database 'main' on server 'blogging.db'. Opened connection to database 'main' on server '/Users/yufei/Developer/aspnetcore/HelloWorld/HelloWorld/blogging.db'. Executing DbCommand [Parameters=[], CommandType='Text', CommandTimeout='30'] PRAGMA foreign_keys=ON; Executed DbCommand (0ms) [Parameters=[], CommandType='Text', CommandTimeout='30'] PRAGMA foreign_keys=ON; Opening connection to database 'main' on server 'blogging.db'. Opened connection to database 'main' on server '/Users/yufei/Developer/aspnetcore/HelloWorld/HelloWorld/blogging.db'. Executing DbCommand [Parameters=[], CommandType='Text', CommandTimeout='30'] PRAGMA foreign_keys=ON; Executed DbCommand (0ms) [Parameters=[], CommandType='Text', CommandTimeout='30'] PRAGMA foreign_keys=ON; Executing DbCommand [Parameters=[], CommandType='Text', CommandTimeout='30'] SELECT COUNT(*) FROM "sqlite_master" WHERE "name" = '__EFMigrationsHistory' AND "type" = 'table'; Executed DbCommand (0ms) [Parameters=[], CommandType='Text', CommandTimeout='30'] SELECT COUNT(*) FROM "sqlite_master" WHERE "name" = '__EFMigrationsHistory' AND