How to build query with selecting by value of foreign object's field

Question

What is the best way for querying by using the value of foreign object\'s field?

Suppose I have these three classes.

UnitResult class which describes amount

Answer 1

So how can I query all UnitResult where Unit type is UnitType.JUICES?

The way to do this in ORMLite is to use the `Where.in(...) with a sub-query:

// setup our sub-query on the Unit table first
QueryBuilder uQb = unitDao.queryBuilder();
uQb.where().eq(Unit.TYPE_FIELD_NAME, UnitType.JUICES);
// outer query on UnitResult table
QueryBuilder urQb = unitResultDao.queryBuilder();
// in using the sub-query
urQb.where().in(UnitResult.UNIT_COLUMN_NAME, uQb);
List results = urQb.query();