What is a View A 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 data The Illustration is made in the next slide.
What is a View Remember that the view exists as query and not as a table
Creating Views The SQL syntax for creating a view is as follows: Create view <viewName> As …QUERY that results in a table/data… GO Example: Consider a student table: Create view NameList As Select regno,name from student go View
Using Views After creating a view, it can used as if it is a table. It can queried like a normal table: Select * from nameList The above query on the view will return: Thus, a view provides a good level of abstraction over the database.
Modifying Views An existing view is modified like using the alter view statement. The Syntax Alter view <viewName> As …QUERY that results in a table/data… GO Similar to the alter procedure statement, the alter table command redefines the existing view defenition.
Deleting Views The Syntax: Drop view <viewName> Example: Drop view nameList
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