It seems that a table trigger is not fired when sdo_geometry object is updated.

Running Oracle 10.2 with Spatial Option.  My question : is it the intended behaviour of Oracle , that when an sdo_geometry object is updated, a table trigger (after insert or update or delete) is not fired ?  My trigger refreshes a materialized view when any data on the base table is changed (except the sdo_geometry column).  And if this how Oracle works, is there a known work-a-round ?

Thanks in advance !!!