Adding relationship
Relationship tables define the relationship between two tables, based on a column that is present in both tables. Sometimes the data you extract may come from related tables. For example, you might want to define a relationship between the tables Purchase Order header and Purchase Order Line, where the Purchase Order Line table is dependent on the Purchase Order header table. The tables would be joined on the Purchase ID column common to both the tables.
A relationship is a reusable block of code and relationship tables can be used during mapping instead of having to type SQL syntax repeatedly.
Add a relationship as