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自动生成的备用键

entity-framework-core .net-core entity-framework sql c#

Jeremy Smith · 技术社区 · 7 年前

EF核心正在生成备用密钥( AK_UserRoles_UserId_RoleId )对于以下数据模型:

数据模型

 public class User : IdentityUser<Guid>
{
    [MaxLength(50)]
    public String FirstName { get; set; }

    [MaxLength(50)]
    public String LastName { get; set; }

    public virtual ICollection<UserRole> UserRoles { get; set; }
}

public class Role : IdentityRole<Guid>
{
    public string Description { get; set; }

    public virtual ICollection<UserGroupToRole> UserGroups { get; set; }
}


public class UserRole : IdentityUserRole<Guid>
{
    public Guid Id { get; set; }

    public virtual User User { get; set; }

    public virtual Role Role { get; set; }

    public int? EntityId { get; set; }

    public string EntityType { get; set; }
}

模型生成器

    protected override void OnModelCreating(ModelBuilder builder)
    {
        base.OnModelCreating(builder);

        builder.Entity<User>(i =>
        {
            i.ToTable("Users");
            i.HasKey(x => x.Id);
            i.Property(u => u.Id).HasDefaultValueSql("NEWID()");

            i.HasMany(u => u.UserRoles)
                .WithOne(ur => ur.User)
                .HasForeignKey(ur => ur.UserId)
                .IsRequired();
        });

        builder.Entity<Role>(i =>
        {
            i.ToTable("Roles");
            i.HasKey(x => x.Id);
            i.Property(u => u.Id).HasDefaultValueSql("NEWID()");
            i.HasMany(x => x.UserGroups);

            i.HasMany<UserRole>()
                .WithOne(ur => ur.Role)
                .HasForeignKey(ur => ur.RoleId)
                .IsRequired();
        });

        builder.Entity<UserRole>(i =>
        {
            i.ToTable("UserRoles");
            i.HasKey(x => x.Id);
            i.Property(x => x.Id).HasDefaultValueSql("NEWID()");
            i.HasIndex(x => new { x.UserId, x.RoleId, x.EntityId, x.EntityType }).IsUnique();
        });

    }

结果迁移

 migrationBuilder.CreateTable(
            name: "UserRoles",
            columns: table => new
            {
                Id = table.Column<Guid>(nullable: false, defaultValueSql: "NEWID()"),
                EntityId = table.Column<int>(nullable: true),
                EntityType = table.Column<string>(nullable: false),
                RoleId = table.Column<Guid>(nullable: false),
                UserId = table.Column<Guid>(nullable: false)
            },
            constraints: table =>
            {
                table.PrimaryKey("PK_UserRoles", x => x.Id);
                table.UniqueConstraint("AK_UserRoles_UserId_RoleId", x => new { x.UserId, x.RoleId });
                table.ForeignKey(
                    name: "FK_UserRoles_Roles_RoleId",
                    column: x => x.RoleId,
                    principalTable: "Roles",
                    principalColumn: "Id",
                    onDelete: ReferentialAction.Cascade);
                table.ForeignKey(
                    name: "FK_UserRoles_Users_UserId",
                    column: x => x.UserId,
                    principalTable: "Users",
                    principalColumn: "Id",
                    onDelete: ReferentialAction.Cascade);
            });

这个 AK用户角色 以上就是问题所在。我不希望这成为限制。如何调整模型以允许约定不应用唯一约束,或者在模型生成器中如何调整?

1 回复 | 直到 7 年前

Ivan Stoev 7 年前

EF核心不会自动生成备用密钥。在这种特殊情况下,它的生成是因为 IdentityDbContext 实施(内部 base.OnModelCreating(builder); 呼叫)正在定义 { UserId, RoleId } 作为 UserRole 表。当您的代码设置 Id 作为主键,ef core并没有取代旧的键,而是将其转换为备用键。

没有用于删除键的Fluent API,因此必须直接使用可变元数据模型。最简单的方法是在定义新的主键之前删除旧的主键:

builder.Entity<UserRole>(i =>
{
    i.Metadata.RemoveKey(i.Metadata.FindPrimaryKey().Properties);
    // ...
});