Row ID values
A row ID is a value that uniquely identifies a row in a table. A column or a variable can have a row ID data type. A ROWID column enables queries to be written that navigate directly to a row in the table.
Each value in a ROWID column must be unique. The database manager maintains the values permanently, even across table reorganizations. When a row is inserted into the table, the database manager generates a value for the ROWID column unless one is supplied. If a value is supplied, it must be a valid row ID value that was previously generated by either DB2® for z/OS® or Db2® for i.
The internal representation of a row ID value is transparent to the user. The value is never subject to CCSID conversion because it is considered to contain BIT data. The length attribute of a ROWID column is 40.