Within LANSA, there are three levels at which business rules can be defined. The levels of the validation hierarchy include:
The order in which validation rules are performed at execution time is Function/Component Level, then Field Level and lastly Table Level. Your programs may perform RDML coded checks before they perform database operations. The field and table validation rules are not called until the program performs a database operation using the Object Access Module (OAM).
The order of importance of the validation hierarchy is defined as Field, then Table and lastly Function/Component. For a field to be used in a table, it must be defined to the Repository first. If the same field is used in three different tables, all three tables will all refer to the same Repository field. Consequently, each table will use the same field level validation rules for that specific field. (This logic is also true of multiple programs which use one table.) Hence, field rules are included in tables which are then used by functions/components. Even though a function/component level check may be performed before the field and table checks, the field and table checks are considered higher in the hierarchy because they provide ultimate control of your validations.
Almost all validations will be specified at table level. (Refer to Field versus Table Level Rules.)