Scenario: A social media platform wants to implement a recommendation system based on users' connections and interactions. Which type of database would be most suitable for storing and querying this data, considering its highly interconnected nature?
- Document Database
- Graph Database
- NoSQL Database
- Relational Database
For a recommendation system based on interconnected data, a Graph Database would be most suitable. Graph databases excel at representing and querying relationships between entities, making them ideal for scenarios where the connections between data points are crucial, such as social networks.
_______ is a technique used to improve query performance by limiting the partitions that need to be scanned.
- Clustering
- Indexing
- Replication
- Sharding
Sharding is a technique used to improve query performance by limiting the partitions that need to be scanned. It involves dividing a large database into smaller, more manageable parts called shards, which can be processed independently.
What is the purpose of generalization in database design?
- Combining similar entities into a higher-level entity
- Establishing one-to-one relationships
- Separating dissimilar entities into distinct tables
- Storing duplicate data
Generalization in database design serves the purpose of combining similar entities into a higher-level entity, often referred to as a superclass. This helps in simplifying the data model and promoting reusability.
Which type of constraint is commonly used to enforce data integrity at the column level in a relational database?
- CHECK
- FOREIGN KEY
- INDEX
- PRIMARY KEY
The CHECK constraint is commonly used to enforce data integrity at the column level in a relational database. It allows you to define conditions that must be met for the data in a column, ensuring its correctness.
In database design, how do you handle recursive relationships between entities?
- Create a new database for each recursive relationship
- Ignore recursive relationships in database design
- Use a foreign key in the same table to establish the relationship
- Use a separate table to represent the recursive relationship
In handling recursive relationships in database design, you typically use a foreign key within the same table to establish the relationship. This involves referencing the primary key of the same table, allowing an entity to be related to itself. It's a common technique for modeling hierarchical structures.
The concept of slowly changing dimensions is primarily concerned with managing changes in _______ over time.
- Data Structure
- Data Types
- Dimension Attributes
- Dimension Hierarchies
The concept of slowly changing dimensions (SCD) is primarily concerned with managing changes in dimension attributes over time. SCD techniques help capture historical data, allowing analysts to analyze how dimensions evolve and change over different time periods.
Explain the difference between entity integrity and referential integrity.
- Ensuring the accuracy of attribute values in a table
- Ensuring the accuracy of relationships between tables
- Ensuring uniqueness of primary key values in a table
- Maintaining consistency between foreign key and referenced primary key values
Entity integrity focuses on maintaining the accuracy and uniqueness of attribute values within a single table. It ensures that the primary key values are unique, preventing duplicate or null entries in primary key columns. Referential integrity, on the other hand, maintains consistency between foreign key and referenced primary key values across different tables, ensuring that relationships between tables are valid and accurate.
A _______ query language is commonly used for graph traversal and manipulation in graph databases.
- Cypher
- Gremlin
- SPARQL
- SQL
A Cypher query language is commonly used for graph traversal and manipulation in graph databases. Cypher is specifically designed for querying graph data, making it expressive and efficient for tasks such as pattern matching and graph traversal.
A retail company wants to analyze its sales data. It has a fact table containing sales revenue, quantity sold, and discounts applied. What type of information would you expect to find in the corresponding dimension tables?
- Customer information, Product details, Time dimensions
- Employee details, Vendor information, Geographical data
- Inventory details, Market trends, Employee information
- Warehouse details, Shipping information, Payment methods
In the context of a retail company's sales data, corresponding dimension tables would likely include information about customers, products, and time. This allows for analysis based on customer preferences, product performance, and temporal trends.
In column-family stores, data is organized into _______.
- Columns
- Families
- Keyspaces
- Rows
In column-family stores, data is organized into families. A column family is a container for rows that share a similar structure. It is a way of grouping related data together, providing a flexible schema where each row in the family doesn't have to conform to the same set of columns.