1. Database modifications initiated by triggers following modifications to other table rows are performed synchronously. To create asynchronous replications of partial data, snapshot tables can be created and the data to be contained therein can be described in a way similar to that when defining view tables.
2. While a view table is a logical view to physically stored data, the snapshot table contains data that is stored physically. To update the contents of the snapshot table, the REFRESH statement must be issued. If a snapshot table only contains data from a base table and if there is a snapshot log, i.e., a protocol of the modifying operations performed between the last REFRESH statement and the current point in time, then only these modifications are made to the snapshot table. Otherwise, the complete content of the snapshot table is rebuilt.
3. Snapshot tables can only be selected. INSERT, UPDATE, or DELETE statements are not possible on snapshot tables.