[firebird-support] Store Procedure that Updates

[Lars]

Hello

I have a stored procedure that updates a record based on a specific condition 
(see below)

  NEWTRAN = GEN_ID(SEQ_TRAN,1);
  
  UPDATE INVENTORY 
  SET   QUANTITY = :NEWQUANT , TRANID = :NEWTRAN
  WHERE RECORDID = :RECORDID AND TRANID = :OLDTRANID;
  
  
  SELECT TRANSID,QUANTITY
  FROM INVENTORY
  WHERE RECORDID = :RECORDID
  into :NEWTRAN2, :NEWQUANT2  <-- return values
  
  if (NEWTRAN <> NEWTRAN2) THEN 
  BEGIN
    NEWTRAN2 = 0;   
    NEWQUANT2 = 0;
  END
    SUSPEND;

If 2 users tried updating same record with this SP, would they collide or would 
one be successful and one fail?   Would the result of the Update statement be 
visible to another transaction or would the SP need to complete and return its 
values in order for the updates to be seen in another users transaction?

I am assuming that the update is visible which is why I will return 0 values 
indicating update was not done, otherwise caller gets to see new TranID and new 
value which matches.

Thanks for reading this.


- Lou