Gianfranco,
Have you ever altered a view before? It seems like in DB2 you can't alter the DDL in a view when you alter a view and only regenerate the ddl.
https://www.ibm.com/support/knowledgecenter/SSEPEK_10.0.0/sqlref/src/tpc/db2z_sql_alterview.html
I thought you could alter the DDL but maybe I am just thinking of SQL Server and not DB2....
Thanks!
Robert