# Basic CS-Data Structures [3i Infotech Placement]: Sample Questions 4 - 5 of 52

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## Question 4

Data Structures

### Question

MCQ▾

Which Statement would you use to remove the EMPLOYEE_Id_PK PRIMARY KEY constraint and all depending constraints from the employee table?

### Choices

Choice (4)

a.

ALTER TABLE employee DROP PRIMARY KEY CASCADE

b.

MODIFY TABLE employee DELETE PRIMARY KEY employee_id_pk CASCADE

c.

MODIFY TABLE employee DROP CONSTRAINT employee_id_pk CASCADE

d.

ALTER TABLE employee DROP PRIMARY KEY employee_id_pk CASCADE

a.

### Explanation

ALTER TABLE employee DROP PRIMARY KEY CASCADE removes the EMPLOYEE _ID_PKPRIMARY KEY constraint and all depending constraints from the EMPLOYEE table.

## Question 5

Data Structures
Edit

### Describe in Detail

Essay▾

There are 8, 15,13, 14 nodes in 4 different trees. Which of them could form a full binary tree?

### Explanation

• There are 8, 15,13, 14 nodes in 4 different trees- of these tree with 15 nodes could be a full binary tree.
• There are 2n-1 nodes in a full binary tree.

## Method of Elimination

• Full binary trees contain odd number of nodes- 8 and 14 nodes cannot be full binary trees.
• 13 nodes can form a complete binary tree but not a full binary tree.
• So, 15 nodes is a correct answer.

Bellow given full binary tree and complete binary tree:

• A complete Binary Tree has all levels completely filled except possibly the last level and the last level has all keys towards as much to the left as possible.
• All full binary trees are complete binary trees, but all complete binary trees are not full binary trees.

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