Row ID assignments

A row ID value can only be assigned to a column, parameter, or variable with a row ID data type. For the value of the ROWID column, the column must be defined as GENERATED BY DEFAULT or OVERRIDING SYSTEM VALUE must be specified. A unique constraint is implicitly added to every table that has a ROWID column that guarantees that every ROWID value is unique. The value that is specified for the column must be a valid row ID value that was previously generated by DB2® for z/OS® or Db2® for i.