Entity Framework Core 3.1代码第一个唯一约束不起作用

Question

很好的问题很清楚。这是我在OnModelCreating类中的dbContext方法：

modelBuilder.Entity<States>(entity =>
            {
                entity.ToTable("States");

                modelBuilder.Entity<States>()
                .HasIndex(p => new { p.State })
                .HasFilter("[State] IS NOT NULL")
                .HasFilter("[Code] IS NOT NULL")
                .IncludeProperties(p => new
                {
                    p.Code
                })
                .IsUnique();

我也尝试过.IsUnique(true)，但它不起作用。

这是正在生成的迁移代码：

protected override void Up(MigrationBuilder migrationBuilder)
{
        migrationBuilder.CreateTable(
            name: "States",
            columns: table => new
            {
                Id = table.Column<int>(nullable: false)
                    .Annotation("SqlServer:Identity", "1, 1"),
                State = table.Column<string>(maxLength: 30, nullable: true),
                Code = table.Column<string>(maxLength: 3, nullable: true),
                Description = table.Column<string>(nullable: true)
            },
            constraints: table =>
            {
                table.PrimaryKey("PK_States", x => x.Id);
            });

        migrationBuilder.CreateIndex(
            name: "IX_States_State",
            table: "States",
            column: "State",
            unique: true,
            filter: "[Code] IS NOT NULL")
            .Annotation("SqlServer:Include", new[] { "Code" });
}

这是我正在生成的表的SQL查询：

CREATE TABLE [dbo].[States]
(
    [Id] [INT] IDENTITY(1,1) NOT NULL,
    [State] [NVARCHAR](30) NULL,
    [Code] [NVARCHAR](3) NULL,
    [Description] [NVARCHAR](MAX) NULL,

    CONSTRAINT [PK_States] 
        PRIMARY KEY CLUSTERED ([Id] ASC)
                    WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, 
                          IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, 
                          ALLOW_PAGE_LOCKS = ON) ON [PRIMARY]
) ON [PRIMARY] TEXTIMAGE_ON [PRIMARY]
GO

您可以看到这些列不是唯一的并且可以为空。

我在这里想念什么？

Answer 1

首先，由于您希望列和状态代码不可为空，因此需要使用注释[Required]进行声明：