具有继承映射的 linq2db 插入

Question

我正在尝试测试一个复杂的 linq2db 映射示例，其中包括继承映射和嵌入式对象。我按照测试项目中的示例进行操作，但在插入操作时出现异常。我没有在测试项目中找到任何插入或更新操作的例子，所以可能我做错了什么。

    [Table]
    [Column("SomeString", "SomeModel.SomeString")]
    [InheritanceMapping(Code = "code1", Type = typeof(Child1))]
    [InheritanceMapping(Code = "code2", Type = typeof(Child2))]
    public abstract class Parent
    {
        [PrimaryKey]
        public int Id { get; }

        public SomeModel SomeModel { get; private set; }

        [Column(IsDiscriminator = true)]
        public string DType { get; set; }

        protected Parent(int id, SomeModel someModel)
        {
            Id = id;
            SomeModel = someModel;
        }
    }

    public class SomeModel
    {
        public SomeModel(string someString)
        {
            SomeString = someString;
        }

        [NotNull]
        public string SomeString { get; }

        internal SomeModel()
        {
        }
    }

    public class Child1 : Parent
    {
        public Child1(int id, SomeModel someModel, int threshold) : base(id, someModel)
        {
            Threshold = threshold;
            DType = "child1";
        }

        [Column]
        public int Threshold { get; }
    }

    public class Child2 : Parent
    {
        public Child2(int id, SomeModel someModel, string code) : base(id, someModel)
        {
            Code = code;
            DType = "child2";
        }

        [Column]
        public string Code { get; private set; }
    }

    [Test]
    [TestCase("Dont cast child in insert")]
    [TestCase("Cast child in insert")]
    public void TestInheritanceMapping(string testMode)
    {
        var db = new DbNorthwind();
        db.Execute(@"IF OBJECT_ID('dbo.Parent', 'U') IS NOT NULL 
                        drop table Parent");
        db.CreateTable<Parent>();
        Console.WriteLine(db.GetTable<Child1>().Select(c => c.Threshold).Any());
        switch (testMode)
        {
            case "Dont cast child in insert":
                db.Insert(new Child1(1, new SomeModel("SomeString"), 1));
                db.Insert(new Child2(1, new SomeModel("SomeString"), "somecode!"));
                break;
            case "Cast child in insert":
                db.Insert<Parent>(new Child1(1, new SomeModel("SomeString"), 1));
                db.Insert<Parent>(new Child2(1, new SomeModel("SomeString"), "somecode!"));
                break;
        }
    }

    public class DbNorthwind : DataConnection
    {
        public DbNorthwind() : base("SqlServer", From.ConnectionStrings.Get("storage.sqlserver"))
        {
        }
    }

在 "Dont cast child in insert" 测试用例中我得到

"System.Data.SqlClient.SqlException : Invalid object name 'Child1'."

在 "Cast child in insert":

"System.ArgumentException : "Threshold" is not a member of type"

但是 table "Parent" 是在 "db.CreateTable();" 步骤中正确创建的：

select 操作似乎也有效

感谢您的帮助！

Answer 1

抱歉回复晚了。

在这种情况下，您应该为父类型指定 table 名称：

[Table("Parent")] // Here it is
[Column("SomeString", "SomeModel.SomeString")]
[InheritanceMapping(Code = "code1", Type = typeof(Child1))]
[InheritanceMapping(Code = "code2", Type = typeof(Child2))]
public abstract class Parent
{
    //...
}

具有继承映射的 linq2db 插入

linq2db insert with inheritance mapping

c#

orm

linq2db