Question

我在az deployment create \ -n demoEmptyRG \ -l southcentralus \ --template-uri https://raw.githubusercontent.com/Azure/azure-docs-json-samples/master/azure-resource-manager/emptyRG.json \ --parameters rgName=demoRG rgLocation=northcentralus

中定义了以下内容

DbContext

但是当我插入几个订单时，每次都使用相同的代码：

protected override void OnModelCreating(ModelBuilder builder)
{
    builder.Entity<Order>().HasAlternateKey(o => o.OrderNumber);

    base.OnModelCreating(builder);
}

即使它们都具有相同的var order = new Order() { OrderNumber = "12345", OrderParts = new List<OrderPartQuantity>() { new OrderPartQuantity() { Part = _context.Parts.FirstOrDefault(p => p.BellNumber == "100123"), Quantity = 10 } } }; _context.Orders.Add(Order); _context.SaveChanges();值，每次也会插入该订单。

我是否理解不正确，或者我缺少什么？我正在为此寻找一个解释

Answer 1

因此，似乎在HasAlternateKey中调用OnModelBuilding实际上需要进行新的数据库迁移。

致电后

Add-Migration TestHasAlternateKeys

此迁移已创建

public partial class HasAlternateKeyTest : Migration
{
    protected override void Up(MigrationBuilder migrationBuilder)
    {
        migrationBuilder.AlterColumn<string>(
            name: "OrderNumber",
            table: "Orders",
            nullable: false,
            oldClrType: typeof(string),
            oldNullable: true);

        migrationBuilder.AddUniqueConstraint(
            name: "AK_Orders_OrderNumber",
            table: "Orders",
            column: "OrderNumber");
    }

    protected override void Down(MigrationBuilder migrationBuilder)
    {
        migrationBuilder.DropUniqueConstraint(
            name: "AK_Orders_OrderNumber",
            table: "Orders");

        migrationBuilder.AlterColumn<string>(
            name: "OrderNumber",
            table: "Orders",
            nullable: true,
            oldClrType: typeof(string));
    }
}

现在，致电后

Update-Database

我不能再重复该列

HasAlternateKey允许重复条目

1 个答案: