13th Day of Oracle Learning

First, the constraint: Skip, MSSQL is not very used

Second, view: This is still more useful, especially when working with other companies, often provide a view of each other

1. Create VIEW: Created OR REPLACE view XX as SELECT * from XXX; Easy update with "OR REPLACE"

Default Scott user does not have View permissions created

2. The View data dictionary User_views

3. View Add Data: Single table can, but if insert into view, will only increase the view contains this data, the remaining table field will be filled with NULL, if not NULL will be an error.

4. View Update data: Single table can

5. View multiple table Insert or UPDATE: Will "Unable to modify multiple base tables through the Join view"

6, delete data: Single table can, but multi-table association will only delete one table, the other table is not deleted

7. With CHECK OPTION: The View creation Criteria field is not updated, but other fields can be updated

8. With Read only: read-only view

9. Remove View: Drop View XXX

13th Day of Oracle Learning