View In Dbms Explain With Examples & Explanations

View In DBMS Explain, What Is View In Dbms Explain With Examples & Explanations

After a table is created and populated with data, it may become necessary to prevent all users from accessing all columns of a table, for data security reasons.
Consider the employee table
Employee(fname, lname,SSN, Bdate address,dno, salary, supSSN)
The company does not want to show the salary of employee to others.
For that reason, company will create a view for the others that view will contain all data except the salary of employee.

Views are logical tables of data extracted from existing tables.
Views do not store any data.
It can be queried just like a table, but does not require disk space .
View stores it ‘s definition in Oracle system catalog.
A view contains no data of its own but it like a window through which data from tables can be viewed or changed.
When a reference is made to a view, its definition is scanned, the base table is opened and the view created on the top of the base table.
It can be used to hide sensitive columns. To do this the owner of the view must grant the select privilege on the view and revoke the privileges on the underlying tables.

A view provides a mechanism to hide certain data from the view of certain users.
 A view is a virtual table.
Some views are used for looking at table data, called as read-only view.
A view that is used to look at table data as well as insert, update and delete table data is called an updatable view.

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