Question

Match List-I with List-II: 

List-I (Key Concepts in Database)	List-II (Description)
(A) Database Schema	(I) Snapshot of the database
(B) Database Instance	(II) Restriction on the type of data
(C) Data Dictionary	(III) Skeleton of the database
(D) Data Constraint	(IV) Database catalog

Choose the correct answer from the options given below: 

• (A) - (III), (B) - (I), (C) - (IV), (D) - (II)
• (A) - (I), (B) - (III), (C) - (II), (D) - (IV)
• (A) - (I), (B) - (II), (C) - (IV), (D) - (III)
• (A) - (III), (B) - (IV), (C) - (I), (D) - (II)

Hint:

Schema = Blueprint Skeleton (does not change frequently).
Instance = Snapshot at a given moment (changes with every INSERT/UPDATE/DELETE).
Dictionary = Catalog Metadata.

Answer 1

The Correct Option is A

Concept:
Relational Database Management Systems rely on fundamental structural terms to distinguish between the overall design, the current contents, the constraints, and the system metadata.

Step 1: Matching Concepts to Their Descriptions:
- (A) Database Schema: The overall logical and physical structure or skeleton of the database system. It defines tables, fields, and relationships, remaining relatively static. Thus, (A) matches with (III).
- (B) Database Instance: The actual collection of data information stored in the database at a particular point in time, often referred to as a snapshot or current state. Thus, (B) matches with (I).
- (C) Data Dictionary: Also known as the system catalog, it stores metadata—the data describing database structure, permissions, and tables. Thus, (C) matches with (IV).
- (D) Data Constraint: Rules applied on table columns to restrict the type or values of data that can be inserted (e.g., NOT NULL, CHECK, UNIQUE). Thus, (D) matches with (II).

Step 2: Formulating the Correct Pairing:
Combining these mappings gives: \[ \text{(A)-(III), (B)-(I), (C)-(IV), (D)-(II)} \] Final Answer:
This sequence corresponds to option (A).