使用 .Net Core (.Net 5) 中的代码优先迁移将 ASPNetUsers 主键数据类型从 nvarchar 更新为 bigint答案

【问题标题】：Updating ASPNetUsers primary key data type from nvarchar to bigint using code first migration in .Net Core (.Net 5)使用 .Net Core (.Net 5) 中的代码优先迁移将 ASPNetUsers 主键数据类型从 nvarchar 更新为 bigint
【发布时间】：2021-09-16 12:39:04
【问题描述】：

这是我将其他字段添加到 ASPNetUsers 表的 ApplicationDbContext.cs 代码。我注意到数据库中的 Identity 生成表将主键 Id 设置为 nvarchar (450)。如何通过代码优先迁移方法将 ASPNetUsers 的 Id 更改为 bigint (Int64)？

public class ApplicationUser : IdentityUser
{
    [Required]
    [StringLength(100)]
    public string FirstName { get; set; }
    [Required]
    [StringLength(100)]
    public string LastName { get; set; }
    [Required]
    [Column(TypeName = "VARCHAR")]
    [StringLength(20)]
    public string SAPNo { get; set; }
    [Required]
    [Column(TypeName = "VARCHAR")]
    [StringLength(150)]
    public string Position { get; set; }
    [Required]
    [Column(TypeName = "VARCHAR")]
    [StringLength(150)]
    public string EmailAddress { get; set; }
    [Required]
    public Int64 DepartmentId { get; set; }
    [Required]
    public int LocationId { get; set; }
    [Required]
    public int RoleId { get; set; }
    [Column(TypeName = "VARCHAR")]
    [StringLength(20)]
    public string CreatedBy { get; set; }
    public string CreatedDate { get; set; }
    public bool IsActive { get; set; } = true;
}

public class ApplicationDbContext : IdentityDbContext<ApplicationUser>
{
    public ApplicationDbContext(DbContextOptions<ApplicationDbContext> options)
        : base(options)
    {
    }
}

【问题讨论】：

为什么要把users表的pk改成int？使用Guids 作为 users/roles 表上的主键的有趣之处在于它们是随机的，不能那么容易猜到。

标签： asp.net-core asp.net-core-mvc asp.net-identity asp.net-core-5.0

【解决方案1】：

我在YouTube 上看到了一个与 EF Core 迁移相关的视频，并且能够将其应用到我的代码中。

1 - 我将 ApplicationDbContext.cs 中的 ApplicationUser 类从 ApplicationUser : IdentityUser 更改为 ApplicationUser : IdentityUser<Int64>，以便 PK 将更新为数据库中的 bigint。如果您希望 PK 仅在数据库中为 int，则可以将其设置为 int。

public class ApplicationUser : IdentityUser<Int64>
{
    [Required]
    [StringLength(100)]
    public string FirstName { get; set; }
    [Required]
    [StringLength(100)]
    public string LastName { get; set; }
    [Required]
    [Column(TypeName = "VARCHAR")]
    [StringLength(20)]
    public string SAPNo { get; set; }
    [Required]
    [Column(TypeName = "VARCHAR")]
    [StringLength(150)]
    public string Position { get; set; }
    [Required]
    [Column(TypeName = "VARCHAR")]
    [StringLength(150)]
    public string EmailAddress { get; set; }
    [Required]
    public Int64 DepartmentId { get; set; }
    [Required]
    public int LocationId { get; set; }
    [Required]
    public int RoleId { get; set; }
    [Column(TypeName = "VARCHAR")]
    [StringLength(20)]
    public string CreatedBy { get; set; }
    public string CreatedDate { get; set; }
    public bool IsActive { get; set; } = true;
}

2 - 我在继承 IdentityRole 的 ApplicationDbContext.cs 中添加了 ApplicationRole 类。留空

public class ApplicationRole : IdentityRole<Int64>
{
}

3 - 我将 ApplicationDbContext.cs 中的 IdentityDbContext 类从 IdentityDbContext<ApplicationUser> 更改为 IdentityDbContext<ApplicationUser,ApplicationRole, Int64>

public class ApplicationDbContext : IdentityDbContext<ApplicationUser,ApplicationRole, Int64>
{
    public ApplicationDbContext(DbContextOptions<ApplicationDbContext> options)
        : base(options)
    {
    }
}

这是 ApplicationDbContext.cs 的完整代码：

public class ApplicationUser : IdentityUser<Int64>
{
    [Required]
    [StringLength(100)]
    public string FirstName { get; set; }
    [Required]
    [StringLength(100)]
    public string LastName { get; set; }
    [Required]
    [Column(TypeName = "VARCHAR")]
    [StringLength(20)]
    public string SAPNo { get; set; }
    [Required]
    [Column(TypeName = "VARCHAR")]
    [StringLength(150)]
    public string Position { get; set; }
    [Required]
    [Column(TypeName = "VARCHAR")]
    [StringLength(150)]
    public string EmailAddress { get; set; }
    [Required]
    public Int64 DepartmentId { get; set; }
    [Required]
    public int LocationId { get; set; }
    [Required]
    public int RoleId { get; set; }
    [Column(TypeName = "VARCHAR")]
    [StringLength(20)]
    public string CreatedBy { get; set; }
    public string CreatedDate { get; set; }
    public bool IsActive { get; set; } = true;
}

public class ApplicationRole : IdentityRole<Int64>
{
}

public class ApplicationDbContext : IdentityDbContext<ApplicationUser,ApplicationRole, Int64>
{
    public ApplicationDbContext(DbContextOptions<ApplicationDbContext> options)
        : base(options)
    {
    }
}

【讨论】：

【解决方案2】：

为什么不用 new 关键字覆盖它。我不确定它是否会起作用，但我假设 EF Core 将使用新 ID 作为主键

public class IdentityUser
{
     public string Id { get; set; }
}

public class ApplicationUser : IdentityUser 
{
      public new long Id { get; set; }
}

【讨论】：

试图迁移这个并在数据库中更新，但没有任何改变