SqliteNetExtensions is it possible to ignore a specified child when calling InsertOrReplaceWithChildren()?

Question

I'm building a mobile app in xamarin that has a lot of relationships between classes. For simplicity consider it to be a "University" app that has the classes: ExamPapers, Students, ExamAnswers.

The ExamPaper class would look like this

public class ExamPapers {
    [ManyToMany(typeof(Student_ExamPaper))]
    public List<Student> Students { get; set; }

    [OneToMany]
    public List<ExamAnswers> Files { get; set; }

    [OneToMany(CascadeOperations = CascadeOperation.All)]
    public List<ExamSection> Sections { get; set; }

    public string ExamName { get; set; }

    [PrimaryKey]
    public string Id { get; set; }
}

So at the moment any sqlitenetextension operation (the ones that end with "WithChildren") will interact with all the relationships when I often just want to interact with one at a time. Here are some example scenarios:

A student "Lana" is just granted access to an ExamPaper "Mathematics 101". Now to grant her access I need to load; all other students with access, all the files for the exam, all the sections. Otherwise these relationships get deleted when I call "InsertOrReplaceWithChildren".
I want to find out the first question in an ExamPaper. I call "GetWithChildren(examId)". I now have an object with a lot of information I don't want (e.g. 300 students and 300 ExamAnswers).

Sorry if I missed something relevant in the documentation, but I've read it through a couple times now. https://bitbucket.org/twincoders/sqlite-net-extensions

Thanks.

score 1 · Accepted Answer · answered Nov 27 '19 at 04:17

Answer on your question in title: No. You cannot.
SQLite-Net-Extensions does not provide such flexible API for manipulating related data.

But there is one helpful thing that can be used in specific cases:

You can work with junction tables as simple tables through SQLite-Net methods (methods without *WithChildren postfix) if junction tables has PrimaryKey (Id).
For example if you have any data which you want to get withoud additional (related) data, just simply call Table</*class*/>() method on specific table with Where(/*your condition*/) clause for getting only data that you really need. Then you can save modified data through Update method.

Unfortunately, this thing will not work with relations update (for example, if you want to move one ExamAnswer from ExamPaper to another ExamPaper object) because all SQLite-Net-Extensions attributes inherited from Ignore SQLite-Net attribute which is ignoring in all SQLite-Net operations.
But there is another one workaround (a little hacky), you can specify second class without any SQLite-Net-Extensions attributes and that's provide you to CRUD any field in specific table.

SqliteNetExtensions is it possible to ignore a specified child when calling InsertOrReplaceWithChildren()?

1 Answers1