Access Route Examples

Access Route Examples

These examples apply to defining an access route within a file definition.

Four related file definitions are used in these examples. These are defined as follows:

File:   ORDHDR ORDLIN CUSMST PROMST Desc:   Order header Order lines Customer master Product master Fields:   ORDNUM CUSTNO DATE ORDNUM ORDLIN QUANTY PRODNO CUSTNO NAME ADDR1 ADDR2 ADDR3 PRODNO DESC PRICE TAXRTE Primary Key 1 ORDNUM ORDNUM CUSTNO PRODNO 2   ORDLIN     Logical Views:   ORDHDRV1O RDLINV1     by key 1 CUSTNO PRODNO

 

To allow complete traversal of this database by users the following access routes would be defined:

File Definition Name Access Route Name File to be Accessed via this Route Max records expected Action to be taken if no records found Key fields/values used for access ORDHDR ORDHRT1 ORDLIN 99 IGNORE ORDNUM ORDHRT2 CUSMST 1 ABORT CUSTNO ORDLIN ORDLRT1 ORDHDR 1 ABORT ORDNUM ORDLRT2 PROMST 1 ABORT PRODNO CUSMST CUSMRT1 ORDHDRV1 9999 IGNORE CUSTNO PROMST PROMRT1 ORDLINV1 9999 IGNORE PRODNO

 

From this table it is easy to see how LANSA can follow the access route chains. For example, say the user nominated PROMST (product master) as a "starting" or "base" file. This would occur:

• Using access route PROMRT1 a route to ORDLIN (order lines) is available (via logical file ORDLINV1) which will access all invoice lines that use the product.

• From ORDLIN the associated order header (ORDHDR) details can be picked up using access route ORDLRT1. The access route ORDLRT2 back to PROMST would be ignored as it forms a "loop".

• From ORDHDR the associated customer details (CUSMST) can be found via access route ORDHRT2. Again ORDHRT1 would be ignored as it forms a "loop".