For question 138 regarding Oracle views, the correct answers are B, E, and G:
* B. The WITH CHECK OPTION clause prevents certain rows from being updated or inserted:
This clause ensures that all data modifications performed through the view result in data that conforms to the view's defining query.
* E. Deleting one or more rows using a view whose defining query contains a GROUP BY clause will cause an error: Views that involve aggregate functions, GROUP BY clauses, or DISTINCT cannot be directly modified with DML operations such as DELETE, because the underlying data manipulation would be ambiguous.
* G. Inserting one or more rows using a view whose defining query contains a GROUP BY clause will cause an error: Similarly to DELETE, INSERT operations into a view that uses a GROUP BY clause are generally not allowed because it's unclear how the new rows should be aggregated into the existing groups.
Other options are incorrect because:
* A: The WITH CHECK OPTION clause does not prevent rows from being displayed; it restricts DML operations.
* C: Views can be created with non-existent underlying tables or views using the FORCE option in Oracle.
* D: Not all views are updatable, especially those involving joins, group functions, or distinct aggregation.
* F: Updating a view does not impact the granted privileges unless the definition of the view changes.