Question

如何限制表AspNetUsers中的UserNameIndex UNIQUE索引？

我正在使用带有Mysql后端的ASP.NET身份，并且正在运行另一个实例：

Index column size too large. The maximum column size is 767 bytes.

我试过了

modelBuilder.Entity<Secuser>().Property(x => x.UserName).HasMaxLength(100);
modelBuilder.Entity<Secuser>().Property(t => t.Id).HasMaxLength(100);

我已经完成了所有标准：

public class Secuser : IdentityUser
 {
 [Required]
 public string FullName { get; set; }

 [Required]
 public string Address { get; set; }

 [Required]
 public string City { get; set; }

 [Required]
 public string Country { get; set; }

 [Required]
 public bool AgreeTermsOfServicePrivacyPolicy { get; set; }

 [Required]
 public string BasePath { get; set; }
}

[DbConfigurationType(typeof(MySqlEFConfiguration))]
public class ApplicationDbContext : IdentityDbContext<Secuser>
{
 public ApplicationDbContext() : base("DefaultConnection")
 {
 }
 .....
 protected override void OnModelCreating(DbModelBuilder modelBuilder)
  {
  modelBuilder.Entity<Secuser>().Property(x => x.UserName).HasMaxLength(100);
  modelBuilder.Entity<Secuser>().Property(t => t.Id).HasMaxLength(100);
  .....
  base.OnModelCreating(modelBuilder);
  }
 }

当我发出：

update-database -verbose

输出是：

Using StartUp project 'sec'.
Using NuGet project 'sec'.
Specify the '-Verbose' flag to view the SQL statements being applied to the target database.
Target database is: 'sec' (DataSource: localhost, Provider: MySql.Data.MySqlClient, Origin: Configuration).
Applying explicit migrations: [201405072209015_InitialCreate].
Applying explicit migration: 201405072209015_InitialCreate.
.....
create table `AspNetUsers` (`Id` nvarchar(128)  not null ,`FullName` longtext not null ,`Address` longtext not null ,`City` longtext not null ,`Country` longtext not null ,`AgreeTermsOfServicePrivacyPolicy` bool not null ,`BasePath` longtext not null ,`Email` nvarchar(256) ,`EmailConfirmed` bool not null ,`PasswordHash` longtext,`SecurityStamp` longtext,`PhoneNumber` longtext,`PhoneNumberConfirmed` bool not null ,`TwoFactorEnabled` bool not null ,`LockoutEndDateUtc` datetime,`LockoutEnabled` bool not null ,`AccessFailedCount` int not null ,`UserName` nvarchar(256)  not null ,primary key ( `Id`) ) engine=InnoDb auto_increment=0
CREATE UNIQUE index  `UserNameIndex` on `AspNetUsers` (`UserName` DESC) using HASH
MySql.Data.MySqlClient.MySqlException (0x80004005): Index column size too large. The maximum column size is 767 bytes.
at MySql.Data.MySqlClient.MySqlStream.ReadPacket()
at MySql.Data.MySqlClient.NativeDriver.GetResult(Int32& affectedRow, Int64& insertedId)
.....

我还进行了更改以允许迁移历史记录工作：

public class MySqlHistoryContext : HistoryContext
 {
 public MySqlHistoryContext(DbConnection connection, string defaultSchema):base(connection,defaultSchema)
  {
  }

 protected override void OnModelCreating(DbModelBuilder modelBuilder)
  {
  base.OnModelCreating(modelBuilder);
  modelBuilder.Entity<HistoryRow>().Property(h => h.MigrationId).HasMaxLength(100).IsRequired();
  modelBuilder.Entity<HistoryRow>().Property(h => h.ContextKey).HasMaxLength(200).IsRequired();
  }
 }

似乎整个问题都围绕着

`UserName` nvarchar(256)

modelBuilder.Entity<Secuser>().Property(x => x.UserName).HasMaxLength(100);

似乎无法正常工作。我正在使用EntityFramework 6.1.0和Microsoft.AspNet.Identity.Core 2.0.1。

所以，看起来似乎是：

ASP.NET-Identity limit UserName length

要么我错过了我实施HasMaxLength的方法，要么就是为什么它不起作用。

Answer 1

简单地说，如果您查看日志（不是那么明显），它会在此查询中崩溃：

CREATE UNIQUE index  `UserNameIndex` on `AspNetUsers` (`UserName` DESC) using HASH

当您查看迁移代码，up（）函数时，默认情况下会看到：

 UserName = c.String(nullable: false, maxLength: 256, storeType: "nvarchar"),

我刚刚将maxLength值更改为196它应该工作。你只需要记住，用户名不能超过196个字符（我认为这对于99.9％的人口来说已经足够了）

PS：我在“AspNetRoles”表中得到了同样的错误

Answer 2

不是在迁移代码中设置最大长度，而是在模型本身上设置它更好。可以使用以下代码完成。

感谢：符文G @ https://stackoverflow.com/a/29059523/332188＆lt; - 在这里解释

只需复制上述链接中的代码即可轻松参考

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<IdentityUser>().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);
    }
}

ASP.NET-Identity限制UserNameIndex长度

2 个答案: