CBSE 2025, Set 4, Q27

Question

Nisha is assigned the task of maintaining the staff data of an organization. She has to store the details of the staff in the SQL table named **EMPLOYEES** with attributes as **EMPNO**, **NAME**, **DEPARTMENT**, **BASICSAL** to store Employee's Identification Number, Name, Department, and Basic Salary respectively. There can be two or more Employees with the same name in the organization.

**(i)** (a) Help Nisha to identify the attribute which should be designated as the PRIMARY KEY. Justify your answer.

**OR**

(b) Help Nisha to identify the constraint which should be applied to the attribute **NAME** such that the Employees' Names cannot be left empty or **NULL** while entering the records but can have duplicate values.

**(ii)** (a) Write the SQL command to change the size of the attribute **BASICSAL** in the table **EMPLOYEES** to allow the maximum value of **99999.99** to be stored in it.

**OR**

(b) Write the SQL command to delete the table **EMPLOYEES**.

Edvaya · Accepted Answer

The correct answer is Subjective. **(i) (a)** The attribute that should be designated as the PRIMARY KEY is **`EMPNO`**. **Justification:** A primary key must uniquely identify each record in a table. `EMPNO` (Employee Identification Number) is unique for every employee, whereas names and departments can be duplicated. --- **OR** **(i) (b)** The constraint that should be applied to the attribute **`NAME`** is the **`NOT NULL`** constraint. This ensures the column cannot be left empty, while still naturally allowing duplicate names. **(ii) (a)** To change the size/data type of an existing attribute, we use the `ALTER TABLE` command with the `MODIFY` clause. The maximum value `99999.99` has 7 total digits with 2 decimal places, so the data type should be defined as `DECIMAL(7,2)`. ```sql ALTER TABLE EMPLOYEES MODIFY BASICSAL DECIMAL(7,2); ``` --- **OR** **(ii) (b)** To completely delete a table and its structure from the database, we use the `DROP TABLE` command. ```sql DROP TABLE EMPLOYEES; ```

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