Validation rules

The validations are stored and implemented from the Data Dictionary (DD aka Metadata repository) into the underlying code, by way of one of the following, with a “weighting” attached to the “seniority” of the validation rule within the Validation Rules Repository (VRR):

the element (field) level globally as defined in DD,
then an element (field) \<-> file level defined within VRR and optionally overriding the global definition
custom user developed validation procedure, optionally overriding any previous validations