Data manipulation through logical views
Data manipulation through Logical Views is limited:
•the UNION ALL operator.
•the DISTINCT function.
The inability to perform data manipulation may take different shapes. An error message may appear. Inability to UPDATE may be signalled by non-updatable fields. Inability to DELETE may be tacit: if the Logical View joins two tables and one does not have all primary key columns named in the view's SQL, then DELETE may be performed only on the other table, without the user being signalled in any way about
If the primary key column(s) of more than one table appear in the SELECT list, manipulations (inserts, updates and deletes) are executed on each of these tables.
If your Logical View does not offer the data manipulation options you want, you can create these options by turning it into a rule-based logical view.
In this Logical View, only the EMPLOYEE table has a primary key in the SELECT list. Therefore only the EMPLOYEE table is updatable through this Logical View:
In this Logical View, both underlying tables has a primary key in the SELECT list. A manipulation on this Logical View will be executed on both tables:
In this Logical View, you can UPDATE the FAMILY_NAME column but not the SALUTATION column, because the SALUTATION column is subject to SQL functions: