Procedure help for loading tables

Question

I am trying to load data from one table to another eg Table A to Table B
I would like the procedure to load all data that has been updated or inserted since last load and delete any rows that have not been
updated since the last load. Can anyone help me please with a procedure for this.
Thanks in advance.

Answer 1

Truncate table B then run something similar to:
DECLARE
-- Assuming you are running this daily and
-- the last_update_date column is populated on every insert/update
CURSOR cura is
SELECT *
FROM tablea
WHERE trunc(last_update_date) = trunc(sysdate);
-- If you run it at a standard interval then
CURSOR cura is
SELECT *
FROM tablea
WHERE trunc(last_update_date) BETWEEN trunc(sysdate - n) AND TRUNC(sysdate);
-- n is the number of days between runs
tabb_rowid ROWID;
BEGIN
   FOR arec in cura LOOP
      BEGIN
         SELECT rowid INTO tabb_rowid
         FROM tableb
         WHERE pk_field1 = arec.pk_field1 and
               pk_field2 = arec.pk_field2;
         UPDATE tableb
         SET pk_field1 = arec.pk_field1,
             pk_field2 = arec.pk_field2,
             field3 = arec.field3,
             field4 = arec.field4
         WHERE rowid = tabb_rowid;
      EXCEPTION WHEN NO_DATA_FOUND THEN
         INSERT INTO tableb
         VALUES (arec.pk_field1,arec.pk_field2,arec.field3,arec.field4);
      END;
   END LOOP;
   COMMIT;
END;