Summary

Important Observations

• Your table OAM needs to be recompiled once access routes are added.

• The type of PJC that can be created is based on the definition of the access route. If the relationship is one to one, only a lookup can be created. If the relationship is one to many, calculation type PJFs can be added.

• PJCs are listed on the Table Columns tab and can be edited from this tab but they cannot be added. You need to add a PJC by first selecting an access route on which the PJC will be based.

• In addition to defining PJCs, access routes are used in LANSA templates to show related tables and in LANSA Client to show linked or joined tables.

Tips and Techniques

• The Keep last parameter on the PJC definition is used to improve performance. It specifies the number of retrieved PJC values to be kept in memory. This value applies to PJCs defined on the access route when the relationship is one to one.

• Be very careful with excessive use of PJCs. There are performance implications of overusing PJCs.

• You can also use trigger functions to perform the same type of calculations or lookup operations that are performed by a PJC.

What I Should Know

• What an access route is.

• How an access route is defined.

• Where access routes are used.

• Where else in LANSA access routes are used.

• What a Predetermined Join Column (PJC) is.

• What operations can be performed by a PJC.

• How to add and maintain PJC definitions.

• What the relationship between PJC and access routes is.