The Query APIs allow you to retrieve data from mobile business objects, to retrieve relationship data and paging data, and to retrieve and filter a query result set.
Retrieving Data from the local database
You can retrieve data from the local database through a variety of queries, including object queries, arbitrary find, and through filtering query result sets.
Retrieving Relationship Data
A relationship between two MBOs allows the parent MBO to access the associated MBO. If the relationship is bi-directional, it also allows the child MBO to access the associated parent MBO.