A view s the dynamic result of one or more relational operations operating on the base
relations to produce another relation. A view is a virtual relation that doesn’t actually
exist n the db but is produced upon request by a particular user, at the time of request.
Purpose of views:
- Customized access of data
- Simplify complex operations on base relations.
- Updates r allowed by query involving a single base relation & containing either
- pkey or cand key of base relation.
- no updates through views which involve multiple base relation.
- no udate through views which involves aggregation or grouping operations.