Scenario: A university has departments and professors. Each department can have multiple professors, and a professor can belong to only one department. How would you represent this scenario in an Entity-Relationship Diagram (ERD)?
- Many-to-Many
- Many-to-One
- One-to-Many
- One-to-One
In this scenario, a One-to-Many relationship would be appropriate. Each department can have multiple professors (One-to-Many), but a professor can belong to only one department. This reflects the constraint that each professor is associated with a single department.
Scenario: An online store has various types of products, including electronics and clothing. Each product has common attributes like name and price, but they also have specific attributes. How would you design the database schema for this scenario?
- Create separate tables for each product type
- Implement a superclass-subclass relationship with a product superclass and electronics/clothing subclasses
- Use a NoSQL database instead of a relational database
- Use a single table for all products with nullable columns for specific attributes
To design the database schema for this scenario, a superclass-subclass relationship with a product superclass and electronics/clothing subclasses is ideal. This allows common attributes like name and price to be stored in the superclass while specific attributes can be stored in the subclasses. It provides flexibility and scalability in the database design.
Scenario: An e-commerce platform needs to store product information, including images, descriptions, and pricing details. The platform wants to scale seamlessly as the number of products increases. Which database model would best suit this requirement and why?
- Columnar Database
- NoSQL Database
- Object-Oriented Database
- Relational Database
A NoSQL Database would be the best fit for this scenario. NoSQL databases, especially those designed for document storage, provide scalability and flexibility for handling diverse product information. The ability to store and retrieve complex data, including images and descriptions, aligns well with the requirements of an e-commerce platform.
In Dimensional Modeling, a _______ table contains descriptive attributes used for analysis.
- Dimension
- Fact
- Lookup
- Reference
In Dimensional Modeling, a Dimension table contains descriptive attributes used for analysis. These attributes provide context and additional information about the measures in the Fact table. For example, in a sales data warehouse, a Date Dimension table might contain attributes like year, quarter, and month.
In a Key-Value Store, the _______ is used to uniquely identify each value.
- Index
- Key
- Key
- Value
In a Key-Value Store, the Key is used to uniquely identify each value. The key serves as a unique identifier that allows efficient retrieval of the associated value. This simplicity is one of the key advantages of Key-Value Stores.
How does data redundancy compare between a Star Schema and a Snowflake Schema?
- Both schemas have equal data redundancy
- Data redundancy is not applicable to either schema
- Snowflake Schema has higher data redundancy
- Star Schema has higher data redundancy
Snowflake Schema typically has higher data redundancy compared to a Star Schema. In a Snowflake Schema, data is normalized into multiple tables, resulting in more duplicate data across different tables. In contrast, a Star Schema denormalizes data into a single table for each dimension, reducing redundancy.
The process of rearranging the physical order of records on disk to match the index order is called _______.
- Clustering
- Defragmentation
- Reorganization
- Sorting
Clustering is the process of rearranging the physical order of records on disk to match the index order. This improves data retrieval efficiency, especially when using direct indexing methods.
How does a Key-Value Store differ from a traditional relational database?
- Organizes data as key-value pairs without a fixed schema
- Stores data in tables with predefined schema
- Supports transactions and ACID properties
- Utilizes complex join operations for querying
A Key-Value Store differs from a traditional relational database by organizing data as key-value pairs without a fixed schema. This provides flexibility, as each record can have different attributes without adhering to a predefined structure, making it suitable for scenarios with evolving or unpredictable data models.
_______ allows users to work on different versions of the data model simultaneously.
- Branching
- Locking
- Merging
- Versioning
Branching in version control allows users to work on different versions of the data model simultaneously. Each branch represents a separate line of development, enabling parallel work without interfering with the main model until changes are merged.
What does a document represent in document-based modeling?
- A collection of related tables
- A file in the file system
- A row in a table
- A self-contained piece of data in the database
In document-based modeling, a document represents a self-contained piece of data in the database. It is typically stored in a format like JSON and contains all the necessary information related to a specific entity or record, allowing for easy retrieval and manipulation.