I have a table with a
Balance column of type
I want to get updates to its
Balance field and reflect the changes in the parents of the updated row.
Currently I can easily subtract parent values by selecting from
deleted table and add to parent values by selecting from
inserted table in two different queries. Since the updates will trigger an other update and so the concept of recursive triggers (enabled in my database) comes to scene, I want to have the minimum number of updates.
Is the following the best way to merge inserted and deleted table and to get the real difference in
Update MyTable Set Balance += updated.Price From ( Select IsNull(inserted.ParentID, deleted.ParentID) As ParentID, (IsNUll(inserted.Balance,0) - IsNull(deleted.Balance,0)) As Price From inserted Full join deleted on inserted.ID = deleted.iD WHERE IsNull(inserted.ParentID, deleted.ParentID) IS NOT NULL ) As updated INNER JOIN MyTable ON MyTable.ID = updated.ParentID Where updated.ParentID IS NOT NULL
For example changing
Balance from 1000 to 800 should yield to -200 change in parent Balance fields.
Also, my code fires the trigger one extra time, so that for an update in level 3 I get 4 updates (trigger-firing) instead of 3.
This is on SQL Server 2012.