Re: help with version checking

Hi all,
  Thanks for all replies, taking into account all your suggestions and 
my google research I arrived to the next script. I'd like to know your 
opinion. Hopefully this will be useful for somebody else.



--------------------------------

--used to stop the script execution on any error
\set ON_ERROR_STOP 1

--disable the autocommit
\set AUTOCOMMIT off

BEGIN;
  /*    Helper function used to check the current version. If it isn't    the expected then raise an error an abort the
installation. */  CREATE OR REPLACE FUNCTION check_version() RETURNS void AS '    DECLARE      current_version VARCHAR;
    needed_version VARCHAR;
 
    BEGIN      --define the expected version      needed_version := ''1.0.0.0'';
      SELECT version INTO current_version FROM agenda_version WHERE id = 1;
      IF current_version <> needed_version THEN        RAISE EXCEPTION ''This script needs Agenda version %, detected 
version %'', needed_version, current_version;        RETURN;      END IF;
      RETURN;
    END;  ' LANGUAGE 'plpgsql';


  /*    Helper function used update the version to the current version.  */  CREATE OR REPLACE FUNCTION
update_version()RETURNS void AS'    DECLARE      current_version VARCHAR;
 
    BEGIN      current_version := ''1.0.0.1'';
      UPDATE agenda_version set version = current_version where id = 1;
      RETURN;    END;  ' LANGUAGE 'plpgsql';



  /*    The first action ALWAYS MUST BE SELECT check_version() to ensure    that the current version is the one needed
forthis changes script.  */  SELECT check_version();
 


  /*    All the actions that must be performed by the changes script  */


  /*    The last actions ALWAYS MUST BE:      SELECT update_version();      DROP FUNCTION check_version();      DROP
FUNCTIONupdate_version();
 
    to update the script version and remove the helper functions  */  SELECT update_version();  DROP FUNCTION
check_version(); DROP FUNCTION update_version();
 



--close the transaction
END;


-- 
Arnau