You do not need to change the command delimiter in Interactive SQL or Sybase Central when you write procedures. However, if you create and test procedures and triggers from some other browsing tool, you may need to change the command delimiter from the semicolon to another character.
Each statement within the procedure ends with a semicolon. For some browsing applications to parse the CREATE PROCEDURE statement itself, you need the command delimiter to be something other than a semicolon.
If you are using an application that requires changing the command delimiter, a good choice is to use two semicolons as the command delimiter (;;) or a question mark (?) if the system does not permit a multi-character delimiter.