The OpenEdge ROWID function returns the unique internal identifier of the database record currently associated with the record buffer you name. This internal identifier has the data type ROWID, which is supported for OpenEdge and all other DataServer databases.
The dataserver designates a column to support the ROWID column. It evaluates the indexes available for a table and selects one in the following order:
PROGRESS_RECID column
Unique index on a single, mandatory, NUMBER with precision that is less than 10 or undefined, and scale less than or equal to zero or undefined
PROGRESS_RECID column