7.6 Relationships and LANSA
Relationships play an important role in defining the database built in the LANSA Repository. Relationships are responsible for creating the following physical aspect of a database file:
- access routes
- logical views
- referential integrity validation rules.
LANSA access routes are used by templates and provide important navigation information about the database. The access routes created in LANSA are the direct result of relationships.
Logical views are based on the second & subsequent Parent/Child relationships and the Join relationships between entities. When an Order refers to a Customer, the Order entity will have an additional logical view based on the Customer Code to provide access from Customer to Order.
File validation rules for referential integrity are the direct result of relationships. A validation check that prevents an Order from being deleted when Ordered Products still exist is the result of the Parent/Child relationship between Order and Ordered Product.