MS SQLSERVER:Creating Views
- 1. 13SQL SERVER: CREATING VIEWS
- 2. What is a ViewA View is a query which is stored in a server in the form of an object. The Power of a view lies in the fact that it can be referenced as a table. It provides an abstraction of the underlying data.The Main use of using a view is the security that it offers. A Third-Person may be restricted to view only a portion of a database, while hiding the rest of sensitive dataThe Illustration is made in the next slide.
- 3. What is a ViewRemember that the view exists as query and not as a table
- 4. SQL ViewsPoints to remember about SQL Views: View is inherently a query.
- 5. Changes made in the view will not alter a table. An explicit update must be made to effect a change. All changes can be made in the view except DDL commands
- 6. Views are used to provide additional security over data
- 7. It also prevents unwanted tampering of sensitive data
- 8. Views provide performance benefitsCreating ViewsThe SQL syntax for creating a view is as follows:Create view <viewName>As …QUERY that results in a table/data…GOExample:Consider a student table:Create view NameListAsSelect regno,name from studentgoView
- 9. Using ViewsAfter creating a view, it can used as if it is a table. It can queried like a normal table:Select * from nameListThe above query on the view will return:Thus, a view provides a good level of abstraction over the database.
- 10. Modifying ViewsAn existing view is modified like using the alter view statement.The SyntaxAlter view <viewName>As …QUERY that results in a table/data…GOSimilar to the alter procedure statement, the alter table command redefines the existing view defenition.
- 11. Deleting ViewsThe Syntax:Drop view <viewName>Example:Drop view nameList
- 12. Summary13. Creating Views About Views
- 13. Creating Views
- 14. Modifying Views
- 15. Deleting ViewsVisit more self help tutorialsPick a tutorial of your choice and browse through it at your own pace.The tutorials section is free, self-guiding and will not involve any additional support.Visit us at www.dataminingtools.net