Views

A view can be seen as a named query, or as a wrapper around a SELECT statement. Views are essential building blocks of relational databases from the UML modeling perspective; a view can be thought of as a method for a UML class. Views share several advantages over procedures, so the following benefits are shared between views and stored procedures. Views can be used for the following purposes:

• Simplifying complex queries and increasing code modularity
• Tuning performance by caching the view results for later use
• Decreasing the amount of SQL code
• Bridging the gap between relational databases and OO languages—especially updatable views
• Implementing authorization at the row level by leaving out rows that do not meet a certain predicate
• Implementing interfaces and the abstraction layer between high level languages and relational databases
• Implementing last minute changes without redeploying the software

Unlike stored procedures, the views dependency tree is maintained in the database;...