Table-Level User-Defined Supplemental
Log Groups
SQL> ALTER TABLE ALLINSURED
ADD SUPPLEMENTAL LOG GROUP allins_polno (POL_NO,
SALES_ID);
The above statement creates a log group
named allins_polno on table ALLINSURED. Since the ALWAYS
clause was omitted, before-images of the columns will be logged
only if at least one of the columns is updated.
In user-defined supplemental log groups, a
column can belong to more than one supplemental log group;
however, the before-image of the columns gets logged only once.
If the same columns are specified to be logged both
conditionally and unconditionally, the columns are logged
unconditionally.
Staging and
Propagation Process
Event propagation is the basis for the
Streams methodology which does replication to other databases.
Propagation of events always occurs between a source queue and a
destination queue.
