Access Route Examples

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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
Primary Key	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
ORDHDR	ORDHRT2	CUSMST	1	ABORT	CUSTNO
ORDLIN	ORDLRT1	ORDHDR	1	ABORT	ORDNUM
ORDLIN	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".

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