How to use OnUpdate = "CASCADE" in ServiceStack.OrmLite

Question

I am trying to understand what the OnUpdate = "CASCADE" parameter does , and how to use it.

In the ForeignKeyAttributeTests (ServiceStack.OrmLite on Github) , the Test CascadesOnDelete is very clear :

    [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);
        }
    }

But there is no test to see how OnUpdate works, and how to cascade updates, can you help me with a small unit test that shows the use of OnUpdate = "CASCADE" ?

Here is the Types used in the Tests :

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

A CASCADE action on Update is simply updating the reference in the Child object. To be able to seethe result you need to change the reference (object id) on the Parent object, save it and then have a look at the value of the Child object. The value must match.

In other word using your sample: Updating the Id property of a ReferencedType object should update the RefId property of all TypeWithOnDeleteAndUpdateCascade object referencing it.

I assume the following test case should answer your question:

[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.
    }
}