Error in mru : ORA-20001: Error in MRU: row= 1 Current version of data ...

Question

hi i am getting tihs error msg
Error in mru internal routine: ORA-20001: Error in MRU: row= 1, ORA-20001: ORA-20001: Current version of data in database has changed since user initiated update process. current checksum
i'll try to show a form table in which i can edit and add data
when i use the wizzard it is all fine with editing but i cant creat a new item because i have to insert my primary key and that shoud be done automatically.
ok again
my PK is at first col1 and second col2
i got a dropdown list in which i choose an item from col1 to just show items in my form with that value, here are more than one results possible
no i want to edit col2 up to col4
or add a line with the same col1 but different col2 and some col3-col4 values
but if i add a line i want to insert col2 to up to col4 (and the PK from col1 shoud be automatically insert from my dropwdown list i choosed before)
i want in col2 an drop down list
so all this works fine i got all the changes i want but when i try do save or update my changes i got the error frome above
i think the problem is at the primary key thing cause i want to choose a part manually but i have to
to get the new line actually u use the add row link but i use instead after my select statement an
Union select :P62_PNR_VOll, null, null, null from dual
to get my first pk automatically from my dropdown element (in my case :P62_PNR_VOLL)
how can i solve that error?
thx for ur help
regadrs
Falk

Answer 1

Hi Falk,
It is usually best to have a sequence number for the primary key on a table. If you need to restrict other fields to be unique, then you can create a constraint to do this.
To create a sequence number and apply this to a new record, you need to do two things:
Let us say that you have a table called TABLEX and this has a numeric primary key field of ID. Do the following in the SQL Commands window
1 - Create a sequence SQL object:
CREATE SEQUENCE "TABLEX_ID_SEQ"  MINVALUE 1 MAXVALUE 99999999999999999999999 INCREMENT BY 1 START WITH 1 NOCACHE  NOORDER  NOCYCLE2 - Create a trigger:
CREATE OR REPLACE TRIGGER "TABLEX_BI"
BEFORE
INSERT ON "TABLEX"
FOR EACH ROW
BEGIN
IF :NEW.ID IS NULL THEN
  SELECT TABLEX_ID_SEQ.NEXTVAL INTO :NEW.ID FROM DUAL;
END IF;
END;This needs to be enabled, so run:
ALTER TRIGGER "TABLEX_BI" ENABLEWhen this is done, you then have "An existing trigger" that you can use for your tabular form. When a new record is created, the trigger is run and this checks for a value in the ID field. If this is NULL, then the next value in the sequence is assigned to it.
Primary Keys can be based on other values. You can use any value from the current record - for example, if you need to get the value from the XXX field, you just reference :NEW.XXX You can use this to pass into a function that returns your new primary key value. But I would recommend keeping to one field for your primary key as this makes things a lot simpler later on.
Andy