Question

我试图了解OnUpdate =“CASCADE”参数的作用以及如何使用它。

在ForeignKeyAttributeTests（ServiceStack.OrmLite on Github）中，Test CascadesOnDelete非常明确：

    [Test]
    public void CascadesOnDelete()
    {
        using (var dbConn = ConnectionString.OpenDbConnection())
        {
            dbConn.CreateTable<TypeWithOnDeleteCascade>(true);

            dbConn.Save(new ReferencedType { Id = 1 });
            dbConn.Save(new TypeWithOnDeleteCascade { RefId = 1 });

            Assert.AreEqual(1, dbConn.Select<ReferencedType>().Count);
            Assert.AreEqual(1, dbConn.Select<TypeWithOnDeleteCascade>().Count);

            dbConn.Delete<ReferencedType>(r => r.Id == 1);

            Assert.AreEqual(0, dbConn.Select<ReferencedType>().Count);
            Assert.AreEqual(0, dbConn.Select<TypeWithOnDeleteCascade>().Count);
        }
    }

但是没有测试看OnUpdate如何工作，以及如何级联更新，你能帮助我进行一个小单元测试，显示使用OnUpdate =“CASCADE”吗？

以下是测试中使用的类型：

public class ReferencedType
{
    public int Id { get; set; }
}


public class TypeWithSimpleForeignKey
{
    [AutoIncrement]
    public int Id { get; set; }
    [References(typeof(ReferencedType))]
    public int RefId { get; set; }
}

public class TypeWithOnDeleteCascade
{
    [AutoIncrement]
    public int Id { get; set; }

    [ForeignKey(typeof(ReferencedType), OnDelete = "CASCADE")]
    public int? RefId { get; set; }
}

public class TypeWithOnDeleteAndUpdateCascade
{
    [AutoIncrement]
    public int Id { get; set; }

    [ForeignKey(typeof(ReferencedType), OnDelete = "CASCADE", OnUpdate = "CASCADE")]
    public int? RefId { get; set; }
}

Answer 1

Update上的CASCADE操作只是更新Child对象中的引用。为了能够查看结果，您需要更改Parent对象上的引用（对象ID），保存它，然后查看Child对象的值。该值必须匹配。

换句话说，使用您的示例：更新Id对象的ReferencedType属性应该更新引用它的所有RefId对象的TypeWithOnDeleteAndUpdateCascade属性。

我认为以下测试用例应该回答您的问题：

[Test]
public void CascadesOnUpdate()
{
    using (var dbConn = ConnectionString.OpenDbConnection())
    {
        dbConn.CreateTable<TypeWithOnDeleteAndUpdateCascade>(true);

        dbConn.Save(new ReferencedType { Id = 1 });
        dbConn.Save(new TypeWithOnDeleteAndUpdateCascade { Id = 1, RefId = 1 });

        Assert.AreEqual(1, dbConn.Select<ReferencedType>().Count);
        Assert.AreEqual(1, dbConn.Select<TypeWithOnDeleteAndUpdateCascade>().Count);

        dbConn.Update<ReferencedType>(new { Id = "2" }, p => p.Id== "1");

        TypeWithOnDeleteAndUpdateCascade obj = db.Single<TypeWithOnDeleteAndUpdateCascade>("Id = 1")

        Assert.AreEqual(obj.RefId, 2);
        // making sure that the RefId got updated, because of the cascade.
    }
}

如何在ServiceStack.OrmLite中使用OnUpdate =“CASCADE”

1 个答案: