The validation rules are a subset of the business rules defining constraints on the logical data model. They are expressed in the definitions of entities, domains and attributes.

A property that defines valid input values for a field or record in a table, or a control on a form. Microsoft Access displays the message specified in the ValidationText property when the rule is violated. seera bu'a qabeessummaa View

An expression that can be linked to a change of data so that it is always evaluated when a certain type of data modification is made. A simple form of a trigger.

This process is carried out after the data has been encoded onto an input medium and involves a data vet or validation program. Its purpose is to check that data falls within certain parameters defined by the systems analyst. A judgement as to whether data is valid is made possible by the validation program, but it cannot ensure complete accuracy.