身份实体框架库 - 更新数据库 [MySQL]

Question

我刚刚将 Microsoft.AspNet.Identity.EntityFramework 库更新到了最新版本 (2.0.0.0)，我发现创建表时出现了一些错误。当我生成迁移代码（Up 和 Down 方法）时，我无法将更改上传到数据库，因为我在执行“Updata-Database”时遇到了索引问题

指定的密钥太长；最大密钥长度为 767 字节

要执行的代码：

public override void Up()
    {
        CreateTable(
            "dbo.AspNetRoles",
            c => new
                {
                    Id = c.String(nullable: false, maxLength: 128, storeType: "nvarchar"),
                    Name = c.String(nullable: false, maxLength: 256, storeType: "nvarchar"),
                })
            .PrimaryKey(t => t.Id)
            .Index(t => t.Name, unique: true, name: "RoleNameIndex");

        CreateTable(
            "dbo.AspNetUserRoles",
            c => new
                {
                    UserId = c.String(nullable: false, maxLength: 128, storeType: "nvarchar"),
                    RoleId = c.String(nullable: false, maxLength: 128, storeType: "nvarchar"),
                })
            .PrimaryKey(t => new { t.UserId, t.RoleId })
            .ForeignKey("dbo.AspNetRoles", t => t.RoleId, cascadeDelete: true)
            .ForeignKey("dbo.AspNetUsers", t => t.UserId, cascadeDelete: true)
            .Index(t => t.UserId)
            .Index(t => t.RoleId);

        CreateTable(
            "dbo.AspNetUsers",
            c => new
                {
                    Id = c.String(nullable: false, maxLength: 128, storeType: "nvarchar"),
                    Email = c.String(maxLength: 256, storeType: "nvarchar"),
                    EmailConfirmed = c.Boolean(nullable: false),
                    PasswordHash = c.String(maxLength: 256, storeType: "nvarchar"),
                    SecurityStamp = c.String(maxLength: 256, storeType: "nvarchar"),
                    PhoneNumber = c.String(maxLength: 256, storeType: "nvarchar"),
                    PhoneNumberConfirmed = c.Boolean(nullable: false),
                    TwoFactorEnabled = c.Boolean(nullable: false),
                    LockoutEndDateUtc = c.DateTime(precision: 0),
                    LockoutEnabled = c.Boolean(nullable: false),
                    AccessFailedCount = c.Int(nullable: false),
                    UserName = c.String(nullable: false, maxLength: 256, storeType: "nvarchar"),
                })
            .PrimaryKey(t => t.Id)
            .Index(t => t.UserName, unique: true, name: "UserNameIndex");

        CreateTable(
            "dbo.AspNetUserClaims",
            c => new
                {
                    Id = c.Int(nullable: false, identity: true),
                    UserId = c.String(nullable: false, maxLength: 128, storeType: "nvarchar"),
                    ClaimType = c.String(maxLength: 256, storeType: "nvarchar"),
                    ClaimValue = c.String(maxLength: 256, storeType: "nvarchar"),
                })
            .PrimaryKey(t => t.Id)
            .ForeignKey("dbo.AspNetUsers", t => t.UserId, cascadeDelete: true)
            .Index(t => t.UserId);

        CreateTable(
            "dbo.AspNetUserLogins",
            c => new
                {
                    LoginProvider = c.String(nullable: false, maxLength: 128, storeType: "nvarchar"),
                    ProviderKey = c.String(nullable: false, maxLength: 128, storeType: "nvarchar"),
                    UserId = c.String(nullable: false, maxLength: 128, storeType: "nvarchar"),
                })
            .PrimaryKey(t => new { t.LoginProvider, t.ProviderKey, t.UserId })
            .ForeignKey("dbo.AspNetUsers", t => t.UserId, cascadeDelete: true)
            .Index(t => t.UserId);

    }

    public override void Down()
    {
        DropForeignKey("dbo.AspNetUserRoles", "UserId", "dbo.AspNetUsers");
        DropForeignKey("dbo.AspNetUserLogins", "UserId", "dbo.AspNetUsers");
        DropForeignKey("dbo.AspNetUserClaims", "UserId", "dbo.AspNetUsers");
        DropForeignKey("dbo.AspNetUserRoles", "RoleId", "dbo.AspNetRoles");
        DropIndex("dbo.AspNetUserLogins", new[] { "UserId" });
        DropIndex("dbo.AspNetUserClaims", new[] { "UserId" });
        DropIndex("dbo.AspNetUsers", "UserNameIndex");
        DropIndex("dbo.AspNetUserRoles", new[] { "RoleId" });
        DropIndex("dbo.AspNetUserRoles", new[] { "UserId" });
        DropIndex("dbo.AspNetRoles", "RoleNameIndex");
        DropTable("dbo.AspNetUserLogins");
        DropTable("dbo.AspNetUserClaims");
        DropTable("dbo.AspNetUsers");
        DropTable("dbo.AspNetUserRoles");
        DropTable("dbo.AspNetRoles");
    }

当我使用 Microsoft.AspNet.Identity.EntityFramework 的 1.0.0.0 版本时，更新数据库的代码不同，我没有任何问题

public override void Up()
    {
        CreateTable(
            "dbo.AspNetRoles",
            c => new
                {
                    Id = c.String(nullable: false, maxLength: 128, storeType: "nvarchar"),
                    Name = c.String(nullable: false, maxLength: 256, storeType: "nvarchar"),
                })
            .PrimaryKey(t => t.Id);

        CreateTable(
            "dbo.AspNetUsers",
            c => new
                {
                    Id = c.String(nullable: false, maxLength: 128, storeType: "nvarchar"),
                    UserName = c.String(maxLength: 256, storeType: "nvarchar"),
                    PasswordHash = c.String(maxLength: 256, storeType: "nvarchar"),
                    SecurityStamp = c.String(maxLength: 256, storeType: "nvarchar"),
                    Discriminator = c.String(nullable: false, maxLength: 128, storeType: "nvarchar"),
                })
            .PrimaryKey(t => t.Id);

        CreateTable(
            "dbo.AspNetUserClaims",
            c => new
                {
                    Id = c.Int(nullable: false, identity: true),
                    ClaimType = c.String(maxLength: 256, storeType: "nvarchar"),
                    ClaimValue = c.String(maxLength: 256, storeType: "nvarchar"),
                    User_Id = c.String(nullable: false, maxLength: 128, storeType: "nvarchar"),
                })
            .PrimaryKey(t => t.Id)
            .ForeignKey("dbo.AspNetUsers", t => t.User_Id, cascadeDelete: true)
            .Index(t => t.User_Id);

        CreateTable(
            "dbo.AspNetUserLogins",
            c => new
                {
                    UserId = c.String(nullable: false, maxLength: 128, storeType: "nvarchar"),
                    LoginProvider = c.String(nullable: false, maxLength: 128, storeType: "nvarchar"),
                    ProviderKey = c.String(nullable: false, maxLength: 128, storeType: "nvarchar"),
                })
            .PrimaryKey(t => new { t.UserId, t.LoginProvider, t.ProviderKey })
            .ForeignKey("dbo.AspNetUsers", t => t.UserId, cascadeDelete: true)
            .Index(t => t.UserId);

        CreateTable(
            "dbo.AspNetUserRoles",
            c => new
                {
                    UserId = c.String(nullable: false, maxLength: 128, storeType: "nvarchar"),
                    RoleId = c.String(nullable: false, maxLength: 128, storeType: "nvarchar"),
                })
            .PrimaryKey(t => new { t.UserId, t.RoleId })
            .ForeignKey("dbo.AspNetRoles", t => t.RoleId, cascadeDelete: true)
            .ForeignKey("dbo.AspNetUsers", t => t.UserId, cascadeDelete: true)
            .Index(t => t.UserId)
            .Index(t => t.RoleId);

    }



    public override void Down()
    {
        DropForeignKey("dbo.AspNetUserRoles", "UserId", "dbo.AspNetUsers");
        DropForeignKey("dbo.AspNetUserLogins", "UserId", "dbo.AspNetUsers");
        DropForeignKey("dbo.AspNetUserClaims", "UserId", "dbo.AspNetUsers");
        DropForeignKey("dbo.AspNetUserRoles", "RoleId", "dbo.AspNetRoles");
        DropIndex("dbo.AspNetUserLogins", new[] { "UserId" });
        DropIndex("dbo.AspNetUserClaims", new[] { "UserId" });
        DropIndex("dbo.AspNetUsers", "UserNameIndex");
        DropIndex("dbo.AspNetUserRoles", new[] { "RoleId" });
        DropIndex("dbo.AspNetUserRoles", new[] { "UserId" });
        DropIndex("dbo.AspNetRoles", "RoleNameIndex");
        DropTable("dbo.AspNetUserLogins");
        DropTable("dbo.AspNetUserClaims");
        DropTable("dbo.AspNetUsers");
        DropTable("dbo.AspNetUserRoles");
        DropTable("dbo.AspNetRoles");
    }

谁能帮我解决这个问题？

提前致谢！！

Answer 1

我知道这是一篇旧帖子，但我今天遇到了同样的问题并对此进行了一些调查，并希望分享我的发现和解决方案。

问题是微软在两个版本之间为AspNetRoles的Name列添加了唯一索引，并且由于该列的大小为256，它违反了MySql的索引规则。 AspNetUsers上的Name列也会出现这个问题。

所以，我去分析如何解决这个问题，我认为最正确的做法是减少 Name 列的长度（恕我直言，拥有一个角色/用户真的没有任何理由名字那么长）。

在调查了 IdentityDbContext（它是基类）上的代码后，我认为解决这个问题的最正确方法是覆盖 ApplicationDbContext 中的 OnModelCreating 并像这样调整那里的列大小：

public class ApplicationDbContext : IdentityDbContext<ApplicationUser>
{
    //... default code for ApplicationDbContext

    protected override void OnModelCreating(DbModelBuilder modelBuilder)
    {
        if (modelBuilder == null)
        {
            throw new ArgumentNullException("modelBuilder");
        }

        base.OnModelCreating(modelBuilder);

        modelBuilder.Entity<ApplicationUser>().Property(u => u.UserName).HasMaxLength(128);

        //Uncomment this to have Email length 128 too (not neccessary)
        //modelBuilder.Entity<ApplicationUser>().Property(u => u.Email).HasMaxLength(128);

        modelBuilder.Entity<IdentityRole>().Property(r => r.Name).HasMaxLength(128);
    }
}

此代码将使用 base.OnModelCreating 调用的默认配置初始化身份模型，然后使用我们自己的覆盖在基类中完成的设置。

由于您正在创建迁移项目，因此您需要重新运行迁移创建以获取更新的模型（或手动修改模型以调整列大小）。

这将解决问题，您将拥有 Asp.NET 身份系统的全部功能。

当然，为了在创建项目时不会出现任何错误，您可以只修改迁移代码，但是您的上下文定义的模型会有所不同，这不好并且可能会导致问题。

Answer 2

这可能是由于您的数据库使用了UTF8 排序规则。

解决此问题的一种可能方法是将包含maxLength: 256 的所有代码部分更改为maxLength: 190。

另一个是将数据库上的UTF8 排序规则更改为latin1 或类似的排序规则。

Answer 3

您可能想查看本教程：http://www.asp.net/mvc/tutorials/security/aspnet-identity-using-mysql-storage-with-an-entityframework-mysql-provider - 特别是“添加自定义 MigrationHistory 上下文”部分，它解释了如何设置自定义 HistoryContext 来解决主键大小问题。