Hi Favio.

>> How can I personalize the error messages, when it fails some component of the referential integrity in the update of a database ? <<

You need to use AERRORS() to check for why the tableupdate failed and personalize your message there:

IF !TABLEUPDATE( 0, .F., 'SomeAlias' )
   AERROR( laErrors )
   *** Check for trigger failed
   IF laErrors[1] = 1539
      DO CASE
         *** Insert Trigger
         CASE laErrors[5] = 1
         
         *** Update Trigger
         CASE laErrors[5] = 2
         
         *** Delete Trigger
         CASE laErrors[5] = 3
      ENDCASE
   ENDIF
ENDIF

HTH

Marcia