EF Core with PostgreSQL 16-为GUID创建一个带有“NULLS NOT DISTINCT”的唯一索引

我在一个实体中有一处房产,属于以下类型 Guid 它是唯一的,但可以为空。

由于空GUID等于 00000000-0000-0000-0000-000000000000 ,PostgreSQL不允许我插入Guid为null(全零)的第二条记录,因为它违反了索引约束。

因此,我已尝试配置 NULLS NOT DISTINCT 通过添加 AreNullsDistinct(false) 指数。

public class Employee
{
    [DatabaseGenerated(DatabaseGeneratedOption.Identity)]
    public required Guid Id { get; set; }
    public required string FirstName { get; set; }
    public required string LastName { get; set; }
    public Guid AdObjectId { get; set; } // Link employee back to identity in AD, can be null as some employee might not present in the AD
}

public class DatabaseContext : DbContext
{
    public DbSet<Employee> Employee { get; set; }

    public DatabaseContext(DbContextOptions<DatabaseContext> options) : base(options) { }

    protected override void OnModelCreating(ModelBuilder modelBuilder)
    {
        modelBuilder.Entity<Employee>().HasIndex(e => e.AdObjectId).IsUnique().AreNullsDistinct(false);
    }
}

但是,当我检查DDL时 null不明显 不在索引中:

create table "Employee"
(
    "Id"         uuid                           not null
        constraint "PK_Employee" primary key,
    "FirstName"  text                           not null,
    "LastName"   text                           not null,
    "AdObjectId" uuid                           not null
);

create unique index "IX_Employee_AdObjectId"
    on "Employee" ("AdObjectId");

以下是迁移(仅索引创建部分)供参考:

migrationBuilder.CreateIndex(
    name: "IX_Employee_AdObjectId",
    table: "Employee",
    column: "AdObjectId",
    unique: true)
    .Annotation("Npgsql:NullsDistinct", false);

我想知道,我是否错过了任何额外的配置 null不明显 出现在指数上?

环境详细信息 :

• .NET Core 8
• PostgreSQL 16
• Microsoft.EntityFrameworkCore : 8.0.4
• Microsoft.EntityFrameworkCore.Design : 8.0.4
• Npgsql.EntityFrameworkCore.PostgreSQL : 8.0.4