Question

我试图测试linq2db映射的复杂示例，包括继承映射和嵌入对象。我按照测试项目中的示例，但在插入操作上获得异常。我在测试项目中没有找到任何插入或更新操作的例子，所以也许我做错了。

    [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＆＃34;不要在插入＆＃34;测试用例我

＆＃34; System.Data.SqlClient.SqlException：无效的对象名称＆＃39; Child1＆＃39;。＆＃34;

在插入＆＃34;中的＆＃34; Cast子项：

＆＃34; System.ArgumentException：＆＃34; Threshold＆＃34;不是＆＃34;
类型的成员

然而表＆＃34;父母＆＃34;在＆＃34; db.CreateTable（）;＆＃34;上正确创建步：

此外，选择操作似乎有效

感谢您的帮助！

Answer 1

很抱歉迟到的回复。

在这种情况下，您应该为父类型指定表名：

[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
{
    //...
}

linq2db insert with inheritance mapping

1 个答案: