|INSERT||The row will be inserted into the primary table (in this case contacts).
The ValidFrom column is populated with the current system time in UTC
The ValidTo field is populated with '9999-12-31 23:59:59.999' (the system max time)
No entry is made in the history table.
|UPDATE||The existing row will be moved from the primary table to the history table. When this is done, its ValidTo time is populated with the current system time in UTC.
The existing row is then replaced by the new row in the primary table. The new row will have a ValidFrom of the current system time in UTC and the ValidTo field will be the system max time.
|DELETE||The existing row will be moved from the primary table to the history table with its ValidTo time populated as the current system time in UTC|
No row will be present in the primary table, since the row has been deleted.