DBMS Qn Set 1

What is the purpose of database normalization?

• The purpose of database normalization is to minimize data redundancy and ensure data integrity.

• To simplify database queries by merging tables.

• To increase data redundancy for faster access.

• To enhance the visual representation of data in reports.

Explain the first normal form (1NF) in database normalization.

• 1NF requires that all columns can contain multiple values.

• First Normal Form (1NF) allows duplicate rows in a table.

• First Normal Form (1NF) is only applicable to relational databases.

• First Normal Form (1NF) ensures that all columns in a table contain atomic values and that each row is unique.

What is an entity in an Entity-Relationship model?

• An entity is a distinct object or thing in the real world that can be identified.

• An entity is a process that occurs in the system.

• An entity is a type of relationship between two objects.

• An entity is a collection of attributes that describe a thing.

Define a relationship in the context of Entity-Relationship modeling.

• A relationship is a type of entity.

• A relationship is a graphical representation of data.

• A relationship in Entity-Relationship modeling represents an association between two or more entities.

• A relationship defines the attributes of an entity.

What is the purpose of a primary key in a database?

• To store multiple values in a single record.

• To create relationships between different tables.

• To improve the performance of database queries.

• To uniquely identify each record in a database table.

Describe the ACID properties of transaction management.

• Atomicity, Consistency, Isolation, Accessibility

• ACID properties: Atomicity, Consistency, Isolation, Durability.

• Accuracy, Clarity, Integrity, Reliability

• Atomicity, Concurrency, Isolation, Stability

What does SQL stand for?

• Standard Query Language

• Structured Query Language

• Simple Query Language

• Structured Query List

Write a basic SQL query to select non duplicate value of city columns from a table named 'Students'.

• SELECT non duplicate city FROM Students

• SELECT distinct city FROM Students;

• GET unique city FROM Students;

• SELECT unique city FROM Students;

What is a foreign key and how is it used in databases?

• A foreign key is used to link two tables together in a relational database, enforcing referential integrity.

• A foreign key is used to store large binary files in a database.

• A foreign key is a type of primary key that uniquely identifies a record.

• A foreign key is a special type of index that speeds up data retrieval.

Explain the difference between a relational and a non-relational data model.

• Relational data models store data in JSON format, while non-relational models use XML.

• Relational data models are only used for large datasets, while non-relational models are for small datasets.

• Relational data models use structured tables and relationships, while non-relational data models offer flexible formats without fixed schemas.

• Non-relational data models require strict schemas, while relational models do not.