CODEWITHSUNDEEP
sqloracle-databaseplsql
Bobby
Bobby

Reputation: 594

Query doesn't update all rows

There's quite big table, more than 10 000 000 rows. It has columns OBJ_ID, DATE_OF_CHANGE, USER. And I added a new column, RECORD_ID, it is empty for now. I need to update it so RECORD_ID should have numeric values ascending for OBJ_ID and DATE_OF_CHANGE. I came up with this:

 CREATE SEQUENCE REC_ID_SEQ
      START WITH 1
      INCREMENT BY 1
      CACHE 100;
    /
    CREATE OR REPLACE TRIGGER TRG_REC_ID_SEQ
      BEFORE INSERT ON T_HISTORY
      FOR EACH ROW
    BEGIN
      :NEW.RECORD_ID := REC_ID_SEQ.NEXTVAL;
    END;
    /

    DECLARE
       O_ID NUMBER := 0;
       S_DATE DATE := SYSDATE;
       HIST_NUM NUMBER := 0;       
       LOOP_COUNT NUMBER := 0;

    BEGIN

      FOR O IN (SELECT ROWID ROW_ID, D.* FROM T_HISTORY D ORDER BY D.OBJ_ID, D.DATE_OF_CHANGE)

      LOOP

          LOOP_COUNT := LOOP_COUNT + 1;
          IF O.OBJ_ID != O_ID OR O.DATE_OF_CHANGE!= S_DATE 
          THEN 
            HIST_NUM := HIST_NUM + 1; 
          END IF;


          UPDATE T_HISTORY T SET T.RECORD_ID = HIST_NUM WHERE T.ROWID = O.ROW_ID;     

          O_ID := O.OBJ_ID;
          S_DATE := O.DATE_OF_CHANGE; 

          IF LOOP_COUNT > 100000 THEN
          COMMIT; LOOP_COUNT := 0;
          END IF;

      END LOOP;
    END;
    /

But when the command stops working (no errors) I see that about half of rows were not updated. How do I do this the right way?

Upvotes: 1

Views: 268

Answers (2)

Littlefoot
Littlefoot

Reputation: 143023

Similar to @krokodilko's solution, using analytical function:

MERGE INTO t_history t
     USING (SELECT obj_id,
                   date_of_change,
                   ROW_NUMBER () OVER (ORDER BY obj_id, date_of_change) rn
              FROM t_history) r
        ON (t.obj_id = r.obj_id AND t.date_of_change = r.date_of_change)
WHEN MATCHED
THEN
   UPDATE SET t.record_id = r.rn;

Upvotes: 1

krokodilko
krokodilko

Reputation: 36127

Use MERGE command and rowid pseudocolumn as a substitute of primary key:

merge into T_HISTORY t
using (
  select rownum as xx, t.* 
  from ( 
    select t.*, rowid as x_rowid 
    from T_HISTORY t
    order by OBJ_ID, DATE_OF_CHANGE
  ) t
) xx
on (xx.x_rowid = t.rowid )
when matched then update
set t.RECORD_ID = xx;

Live demo: http://sqlfiddle.com/#!4/aad05/2

Upvotes: 2

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