ForeignCollection not loading with Query Builder

Question

I tried usign OrmLite in an android Application, and encountered a problem:

I created a foreign collection on an object, and assigned it some objects. I can use the queryForAll() Method on the DAO to query the objects, and it returns them as expected:

allTeams = getHelper().getTeamDao().queryForAll();
for(ScrumTeam team : allTeams) {
    if(team.getMembers() == null || team.getMembers().size() == 0) {
        log("No Members");
    } else {
        log(team.getMembers().size()+" Members");
    }
}

This works as expected, printing "2 Members" or "3 Members" on the Teams, representing the correct data.

Obviously, I wanted to sort the data, and the method to do this I found was using the queryBuilder:

allTeams = getHelper().getTeamDao().queryBuilder().selectColumns("id", "name").orderBy("name", true).query();
for(ScrumTeam team : allTeams) {
    if(team.getMembers() == null || team.getMembers().size() == 0) {
        log("No Members");
    } else {
        log(team.getMembers().size()+" Members");
    }
}

The above code outputs "No members", but i can access other data of the team (id and name) perfectly. I tried setting eager to true and false on the collection, but neither worked. Investigating further, I found out, that the members array is not initialized (null). Is this a bug, or am I using the Library incorrectly? Is there a way to fetch the ForeigCollection manually?

Thanks for your replies!

Answer 1

Interesting. The problem is that you have limited the columns to "id" and "name". ORMLite is therefore not creating your ForeignCollection fields for you.

This was a bug was fixed in version 4.30. We've added the ability to specify the ForeignCollection column name in selectColumns(). Here's the bug fix around this:

https://sourceforge.net/tracker/?func=detail&aid=3428751&group_id=297653&atid=1255989

You need to modify your QueryBuilder code to also "select" the members field.

...selectColumns("id", "name", "members")...

Here are the docs for the selectColumns() method:

http://ormlite.com/docs/select-columns

To quote:

WARNING: If you specify any columns to return, then any foreign-collection fields will be returned as null unless their ForeignCollectionField.columnName is also in the list.