v and e are each a record or record field. @
The e and v must have the same structure. They have the same structure if any of the following occur:
Both e and v are fields with the same elementary data type.
Both e and v are records with the same number of fields such that corresponding fields are the same elementary data type.
Both e and v are records with the same number of fields such that corresponding fields are substructures with the same structure as defined in 2, above.
The sections on the RECORD and STRUCTURE statements have more details on the structure of records.