SQL - Structured Query Language SQL View Management Questions and Answers

Question 1

Which of the following is a primary benefit of using a SQL view?

Accepted Answer

To simplify complex queries and restrict access to the underlying base tables.

Answer

To create a physical, permanent copy of the data from one or more tables for faster writes.

Answer

To enforce foreign key constraints between tables.

Answer

To improve the performance of DELETE operations on the underlying tables.

Question 2

A developer needs to create a simplified, read-only representation of employee data, joining the `Employees` table with the `Departments` table to show each employee's name and their department's name. Which SQL statement correctly creates this view?

Accepted Answer

CREATE VIEW V_Employee_Department AS SELECT e.FullName, d.DepartmentName FROM Employees e JOIN Departments d ON e.DeptID = d.DeptID;

Answer

DEFINE VIEW V_Employee_Department AS SELECT e.FullName, d.DepartmentName FROM Employees e JOIN Departments d ON e.DeptID = d.DeptID;

Answer

MAKE VIEW V_Employee_Department SELECT e.FullName, d.DepartmentName FROM Employees e JOIN Departments d ON e.DeptID = d.DeptID;

Answer

CREATE V_Employee_Department AS SELECT e.FullName, d.DepartmentName FROM Employees, Departments;

Question 3

A database administrator needs to modify the underlying query of an existing view named `V_Active_Users` without dropping it, to include a new column. Which SQL command is used for this purpose?

Accepted Answer

ALTER VIEW V_Active_Users AS ...

Answer

MODIFY VIEW V_Active_Users AS ...

Answer

UPDATE VIEW V_Active_Users SET ...

Answer

REPLACE VIEW V_Active_Users WITH ...

Question 4

What is the effect of executing the `DROP VIEW V_Product_Summary;` command on a database?

Accepted Answer

The view's definition is removed from the database, but the data in the underlying base tables is unaffected.

Answer

The view's definition is removed, and all data from the underlying tables is deleted.

Answer

The view is marked as obsolete but remains in the database for historical queries.

Answer

Only the data currently represented by the view is deleted; the view definition and base tables remain.

Question 5

A user attempts to execute an `INSERT` statement on a view. Under which of the following conditions is the operation most likely to fail?

Accepted Answer

The view is based on a join of multiple tables or contains an aggregate function like COUNT().

Answer

The view is based on a single table and references all columns with NOT NULL constraints.

Answer

The view is defined with a simple WHERE clause to filter rows.

Answer

The view has column aliases that are different from the base table's column names.

Question 6

Which of the following statements about SQL views is TRUE?

Accepted Answer

A view can be used to provide a consistent data interface even if the underlying table schemas change.

Answer

Views are primarily used to create indexes on complex queries.

Answer

A view always stores a physical copy of its data, which is refreshed periodically.

Answer

Once a view is defined with `SELECT *`, it automatically includes any new columns added to the base table later.