3.14 Access Routes to Other Files

An access route defines a route or path from one file to another file.

An access path answers the question "Given that I have a record from file A, how do I access the associated record(s) in file B"?

File A is always the file definition that is currently being worked upon. File B can be any other physical or logical file defined using the LANSA system.

File A can have many access routes. They could all be from file A to file B, or some could be to any other file that is related to file A.

In addition, access routes can be followed in a chain. Thus if there is an access route from file A to file B, and an access route from file B to file C, then it is possible to start with a record from file A and locate the associated record(s) in file C.

Access routes are very important to the automatic process definition components of LANSA because:

• Users do not need to understand the database structure. The user only needs to nominate a "base" or "starting" file and LANSA can then follow the access route chains to present the other accessible files as simple alternatives.

• The relationship between records in the 2 files in any access route is predefined as "1: 1" or "1: many". This enables the required screen formats to be automatically designed for the type of information expected.