The routine signature

When a user or another routine invokes a routine, the database server searches for a routine signature that matches the routine name and arguments. If no exact match exists, the database server searches for a substitute routine, as follows:

1. When several arguments are passed to a routine, the database server searches the sysprocedures system catalog table for a routine whose signature is an exact match for the invoked routine:
   1. The database server checks for a candidate routine that has the same data type as the leftmost argument.

      For more information, see Candidate list of routines.

   2. If no exact match exists for the first argument, the database server searches the candidate list of routines using a precedence order of data types.

      For more information, see Precedence list of data types.

2. The database server continues matching the arguments from left to right. If the database contains a routine with a matching signature, the database server executes this routine.