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WorksheetsMidterm Examination on Database Fundamentals
Total questions: 40
Worksheet time: 40mins
Which type of database system is often used in mainframe applications?
Hierarchical databases
Network databases
Relational databases
Object-oriented databases
What type of database stores data in a structured table format with rows and columns?
Document database
Relational database
Graph database
NoSQL database
Which type of database system is best suited for storing unstructured data?
Relational database
Hierarchical database
NoSQL database
Network database
What is an advantage of relational databases?
Simple structure for complex relationships
Efficient data retrieval for structured data
High performance for real-time analytics
Does not require predefined schemas
What does a hierarchical database use to organize data?
Tables and relationships
Nodes and edges
Parent-child tree structure
Documents and collections
A graph database is best suited for which type of data?
Social networks and relationships
Financial transactions
Inventory management
Customer orders
Which database model provides the best flexibility for handling complex relationships?
Relational database
Graph database
Hierarchical database
Document database
How does a document database store information?
In tables with rows and columns
As key-value pairs
As structured documents in JSON or XML
As interconnected nodes and edges
What is a key characteristic of NoSQL databases?
Schema-less design
Strict data consistency
Requires normalization
Uses only SQL for queries
Why might an organization choose a network database?
To manage hierarchical relationships
To model complex, many-to-many relationships
To simplify table-based queries
To improve transaction speed
Which database type is commonly used for web applications and content management systems?
Document databases
Hierarchical databases
Network databases
Object-oriented databases
What is a major disadvantage of hierarchical databases?
Inefficient data retrieval
Lack of support for complex relationships
No indexing support
High storage costs
What advantage do object-oriented databases offer?
Strong consistency and data normalization
Direct support for complex data structures and objects
Better query optimization
Fixed schema structures
Which database type is best for handling massive amounts of time-series data?
NoSQL databases
Hierarchical databases
Relational databases
Graph databases
What is the main use case for a key-value database?
Real-time data processing
Fast lookups for simple queries
Complex relational queries
Storing highly structured data
Which database model requires strict adherence to ACID properties?
Document databases
NoSQL databases
Relational databases
Graph databases
A company needs to store a large dataset that includes hierarchical and complex relationships. Which database type would be most efficient?
Document database
Graph database
Network database
Relational database
How can a hybrid approach improve database performance?
By combining SQL and NoSQL features
By eliminating the need for indexing
By storing data in a single centralized system
By using only relational principles
What challenges arise when transitioning from a relational to a NoSQL database?
Loss of data integrity
Schema migration and query adaptation
Increased indexing speed
Easier transaction management
When should a document database be used over a relational database?
When data relationships are complex
When data is highly structured
When flexible schemas and fast reads are needed
When strict referential integrity is required
What is the main purpose of an Entity-Relationship (ER) model?
To perform database transactions
To visualize and design a database schema
To execute SQL queries
To store raw data in files
What is an entity in an ER model?
A type of database query
A real-world object with attributes
A table in a relational database
A foreign key in a schema
What does an ER diagram primarily depict?
SQL query execution plan
The structure of a relational table
Entities, attributes, and relationships
Indexing strategy in databases
What is the role of a primary key in a database?
Ensures every record has a unique identifier
Links multiple databases together
Stores unstructured data efficiently
Helps execute complex queries faster
What is normalization in database design?
A technique to remove redundancy and improve consistency
A process to speed up SQL queries
A method to combine multiple databases
A way to enforce indexing
In an ER model, what do attributes represent?
The columns in a relational database
The relationships between entities
The constraints in a schema
The operations performed in a database
Why is the process of normalization important in database design?
It removes unnecessary attributes
It reduces data redundancy and increases integrity
It simplifies indexing methods
It improves query execution time
How does a foreign key maintain data integrity?
By enforcing referential constraints between tables
By storing duplicate values across tables
By preventing any updates to data
By eliminating the need for indexing
Which of the following is a key characteristic of the third normal form (3NF)?
Eliminates all multi-valued dependencies
Ensures that every non-key attribute is fully dependent on the primary key
Allows partial dependencies for efficiency
Combines multiple tables for faster access
In an ER diagram, a relationship is typically represented by:
A rectangle
A diamond
A circle
A square
What is a composite key?
A single unique identifier for a record
A combination of two or more attributes that uniquely identify a record
A foreign key linking two tables
A key used for indexing performance
Why might denormalization be used in a database?
To optimize query performance by reducing joins
To eliminate indexing overhead
To enforce data consistency
To improve referential integrity
What does a weak entity require in order to be uniquely identified?
A composite key
A foreign key and an identifying relationship
A primary key
A surrogate key
How does an associative entity function in a database schema?
It connects two or more entities in a many-to-many relationship
It stores metadata about database tables
It replaces foreign keys in relationships
It defines constraints between two databases
What is the main purpose of cardinality in an ER diagram?
To specify the number of entity occurrences in a relationship
To define primary keys
To determine the indexing strategy
To optimize SQL queries
What is an artificial key in a database?
A system-generated unique identifier
A manually created primary key
A composite foreign key
A redundant attribute
A company wants to ensure minimal data redundancy while maintaining query efficiency. Which normalization level should be prioritized?
First normal form (1NF)
Third normal form (3NF)
Boyce-Codd normal form (BCNF)
Denormalization
How can indexing impact database normalization?
It enhances query performance without altering normalization levels
It allows violations of normalization rules
It reduces database schema complexity
It removes the need for foreign keys
When designing a database for a complex application with many interrelated entities, what approach would be most effective?
Use an object-relational model
Implement extensive denormalization
Maintain a fully normalized schema with extensive indexing
Use only primary keys for relationships
How can a database designer ensure data consistency in an ER model?
By defining appropriate constraints such as primary keys and foreign keys
By avoiding normalization
By using only one table for all data
By allowing redundant data for performance reasons
