Data Link Object:

Data  link  object  is  a  data  model  object,  that  joins  multiple  queries.  For a easy master/detail report, two queries will be linked by using primary and foreign keys of the tables from in that data is selected.  The Query with the primary key column that is the source for the master records is known as the parent Query and the Query with the foreign key column that is. The source for the detail records is known as the Child Query.

Linking two tables through primary and foreign keys is same to specifying a join condition. The Information in the data link object is used to join two queries.  A where clause for the join is added to the child query’s SELECT statement at run time.