Star Schema often leads to _______ query performance compared to Snowflake Schema.

  • Better
  • Similar
  • Unpredictable
  • Worse
Star Schema often leads to Better query performance compared to Snowflake Schema. The denormalized structure of Star Schema simplifies query execution by minimizing joins, resulting in faster analytical query performance.

Which type of consistency model ensures that all reads reflect the most recent write for a given data item in a distributed system?

  • Causal Consistency
  • Eventual Consistency
  • Strong Consistency
  • Weak Consistency
Strong Consistency ensures that all reads reflect the most recent write for a given data item in a distributed system. This model guarantees that any read operation will return the most recent write, providing a high level of data consistency but often at the cost of increased latency and reduced availability.

An _______ entity is one that represents a many-to-many relationship between two other entities.

  • Aggregated
  • Associative
  • Atomic
  • Derived
An associative entity is one that represents a many-to-many relationship between two other entities. It is introduced to resolve a many-to-many relationship by breaking it down into two one-to-many relationships, connecting the original entities through the associative entity.

What is the significance of the "column" in a column-family store?

  • It represents a data attribute
  • It represents a foreign key
  • It represents a primary key
  • It represents a record
In a column-family store, the "column" signifies a data attribute. Each column contains a specific piece of information, and rows may have varying columns based on the data they hold. This flexibility allows for dynamic and schema-less data storage, offering versatility in managing diverse datasets.

Scenario: A data analyst needs to query a database to extract specific information for a report. Would they likely use SQL or UML for this task, and why?

  • Both SQL and UML
  • No specific language needed
  • SQL
  • UML
A data analyst would likely use SQL (Structured Query Language) for querying a database to extract specific information for a report. SQL is specifically designed for interacting with databases, allowing the analyst to write queries to retrieve, filter, and manipulate data efficiently. UML, on the other hand, is a modeling language and is not intended for direct database querying.

How does generalization enhance the clarity and efficiency of a data model?

  • Increasing redundancy by duplicating attributes across entities
  • Limiting data abstraction to individual entities
  • Reducing redundancy by defining common characteristics in a superclass
  • Simplifying queries by creating complex relationships
Generalization enhances the clarity and efficiency of a data model by reducing redundancy. Common characteristics are defined in a superclass, and subclasses inherit these attributes, promoting a more organized and maintainable structure.

In clustering, data is organized into _______ based on shared characteristics.

  • Categories
  • Clusters
  • Hierarchies
  • Sets
In clustering, data is organized into clusters based on shared characteristics. Clusters are groups of data points that are similar to each other and dissimilar to data points in other clusters. This helps in discovering patterns and relationships within the data.

Which property of graph databases makes them particularly suitable for recommendation systems and social networks?

  • Ability to store large volumes of structured data
  • Native representation of relationships
  • Support for ACID transactions
  • Use of SQL as the query language
Graph databases are particularly suitable for recommendation systems and social networks due to their native representation of relationships. In a graph database, relationships are first-class citizens, making it efficient to traverse and analyze connections between entities, a key requirement in recommendation systems and social networks.

In Slowly Changing Dimensions (SCD), how does Type 4 handle historical data?

  • Adds new rows for each change
  • Creates separate tables for historical data
  • Overwrites existing historical records
  • Uses effective dating or versioning
Type 4 SCD handles historical data by using effective dating or versioning. Instead of adding new rows, it maintains the original row with an effective date or version number, allowing for a more compact representation of historical changes without cluttering the table with additional rows.

A social media platform needs to store a vast amount of multimedia content, including images and videos. Discuss the considerations they should take into account when implementing compression techniques for this data.

  • Adaptive Compression
  • Image Compression
  • Lossy Compression
  • Video Compression
Considering the large volume of multimedia content, a social media platform should consider Lossy Compression. This method sacrifices some data to achieve higher compression ratios, making it suitable for non-critical content like images and videos where a slight loss in quality is acceptable for significant storage savings.