When and where to use Dbms_Error_Code, Error_Code and SqlCode.

Question

I have gone thru some docs and books on dev to understand error messages in Developer. After reading i am more confused reg the difference between
Dbms_Error_Code, Error_Code and SqlCode.
Can any one tell me concisely the difference and the situation where these are used.
This is my understanding so far.....
DBMS_ERROR_CODE and DBMS_ERROR_TEXT return the last Oracle Server error code and message due to an implicit DML within form application.
SQLCODE and SQLERRM return the last Oracle Server error code and message due to an explicit DML within a form application.
So why use ERROR_CODE at all?
Below is an extract from the Oracle help Docs...
When an implicit DML raises an error, it is handled with an ON-ERROR trigger using the ERROR_CODE function. This function contains the last Oracle Form error code. These errors are prefixed with FRM-.
Okay but why not just use DBMS_ERROR_CODE instead of ERROR_CODE?
Example: /*
** Built-in: DBMS_ERROR_CODE,DBMS_ERROR_TEXT
** Example: Reword certain Oracle Forms error messages by
** evaluating the DBMS error code that caused them
** Trigger: On-Error
DECLARE
errcode NUMBER := ERROR_CODE;
dbmserrcode NUMBER;
dbmserrtext VARCHAR2(200);
BEGIN
IF errcode = 40508 THEN
** Oracle Forms had a problem INSERTing, so
** look at the Database error which
** caused the problem.
dbmserrcode := DBMS_ERROR_CODE;
dbmserrtext := DBMS_ERROR_TEXT;
IF dbmserrcode = -1438 THEN
** ORA-01438 is "value too large for column"
Message('Your number is too large. Try again.');
ELSIF dbmserrcode = -1400 THEN
** ORA-01400 is "Mandatory column is NULL"
Message('You forgot to provide a value. Try again.');
ELSE
** Printout a generic message with the database
** error string in it.
Message('Insert failed because of '||dbmserrtext);
END IF;
END IF;
END;Regards
Gus

Answer 1

Sorry Steve as wonderful as your code example may be you are putting the cart before the horse as far as the purpose of this thread goes. I don't need guidance on HOW to use certain error functions at least not until i know WHEN i should use them and thats why i started this thread. There are 3 different sets of Oracle functions below for use in forms but not enough guidance in the docs as to when to use them for the newcomer to forms. All i need is a simple definition as to when these functions should be used appropriately in forms. The rest I will find out for myself when i start using forms properly (including the use of your wonderful code). At the moment i just want to pass the Forms exam and to have a better understanding of what i am doing.
DBMS_ERROR_CODE & DBMS_ERROR_TEXT
SQLCODE & SQLERRM
ERROR_CODE & ERROR_TEXT
I've got one person saying this....
DBMS_ERROR_TEXT and DBMS_ERROR_CODE built-ins are intended to be used in a form-level ON-ERROR trigger.
SQLCODE and SQLERRM functions are intended to be used in a WHEN OTHERS exception handler.
and another saying ...
Use error_code to handle Forms error
Use dbms_error_code to handle database error
.. then i've got your code which predominantly uses ERROR_CODE.
Then the STS test papers say this...
When an implicit DML raises an error, it is handled with an ON-ERROR trigger using the ERROR_CODE function. This function contains the last Oracle Form error code. These errors are prefixed with FRM-.
Example:
IF ERROR_CODE = 40508 THEN
  MESSAGE ('Invalid insert');
  RAISE FORM_TRIGGER_FAILURE;
END IF;DBMS_ERROR_CODE and DBMS_ERROR_TEXT return the last Oracle Server error code and message due to an implicit DML within form application. These errors are prefixed with ORA-.
SQLCODE and SQLERRM return the last Oracle Server error code and message due to an explicit DML within a form application. These functions must be used in the exception handler of the program unit that issues the DML command.
A little Confusing to say the least!!!
Okay, so is this correct...
SQLCODE and SQLERRM are used with explicit DML within a form application and are used in the exception handler of the program unit that issues the DML command.
When an implicit DML raises an error, it is handled with an ON-ERROR trigger using the ERROR_CODE function. These errors are prefixed with FRM-.
DBMS_ERROR_CODE and DBMS_ERROR_TEXT are also used with implicit DML within form application. These errors are prefixed with ORA-.
So why use DBMS_ERROR_CODE and DBMS_ERROR_TEXT if ERROR_CODE and ERROR_TEXT are to be used in ON-ERROR triggers and if an implicit DML error arises then whats the difference between ERROR_CODE FRM- errors and DBMS_ERROR_CODE ORA- errors? Apart from one being a form error and the other being a server error, what different things do they tell us? If an implicit DML error ocurrs would this generate ORA- and FRM- errors at the same time.
Cheers
Gus
Message was edited by:
gusora