How does version control help in collaboration among data modelers?
- Automating data validation
- Encrypting data models for security
- Facilitating teamwork and tracking changes
- Managing database backups
Version control facilitates collaboration among data modelers by providing a structured system for tracking changes. It enables team members to work on different aspects simultaneously, merge changes, and maintain a history of alterations, promoting efficient teamwork in data modeling projects.
In a column-family store, how is data typically accessed?
- Random access only
- Through SQL queries
- Using complex joins
- Via primary key lookups
In a column-family store, data is typically accessed via primary key lookups. Each row in the column-family is identified by a unique primary key, and accessing data involves querying or retrieving based on this key. This allows for fast and efficient retrieval of specific data records.
The _______ model in NoSQL databases allows for different levels of consistency based on the specific requirements of an application.
- ACID
- BASE
- CAP
- PACELC
The BASE (Basically Available, Soft state, Eventually consistent) model in NoSQL databases allows for different levels of consistency based on the specific requirements of an application. It prioritizes availability and partition tolerance over strong consistency, making it suitable for distributed and scalable systems.
Scenario: A gaming company wants to track user scores and achievements across multiple platforms and devices. How would you design a Key-Value Store solution to handle this requirement, considering data consistency and performance?
- Implementing eventual consistency for better performance
- Storing each user's scores and achievements as separate keys
- Using a relational database for consistent data handling
- Utilizing a distributed file system
In designing a Key-Value Store solution for tracking scores and achievements, storing each user's scores and achievements as separate keys ensures efficient retrieval and update operations. It allows for quick access to specific user data without affecting the overall system performance.
_______ is a technique used to minimize index size and optimize query performance by grouping similar index values together.
- Clustering
- Compression
- Partitioning
- Segmentation
Index compression is a technique used to minimize index size and optimize query performance by grouping similar index values together. It reduces storage requirements and can enhance overall database performance.
Scenario: A social media platform stores user posts, comments, and interactions in its database. Users frequently search for posts by keyword, user ID, or time period. How would you implement indexing to facilitate efficient searching in this scenario?
- Avoid indexing for simplicity in data retrieval
- Create a composite index on user ID and timestamp columns
- Implement a clustered index on the post content column
- Use a full-text search index for keyword searches, and create non-clustered indexes on user ID and timestamp columns
In this scenario, utilizing a full-text search index for keyword searches and creating non-clustered indexes on user ID and timestamp columns would facilitate efficient searching. Full-text search indexes are suitable for textual searches, and non-clustered indexes provide quick access to specific columns.
In Slowly Changing Dimensions (SCD), which technique is commonly used to maintain historical data in a dimension table?
- Delete
- Hybrid
- Insert
- Update
In Slowly Changing Dimensions (SCD), the Insert technique is commonly used to maintain historical data in a dimension table. With this technique, new records are inserted into the dimension table to represent changes, while existing records remain intact, preserving historical information.
What is referential integrity in a database system?
- Enforces the use of indexes on all tables
- Ensures that foreign key values match the primary key values in another table
- Ensures that primary key values are unique
- Validates the data types of columns
Referential integrity in a database system ensures that foreign key values in one table match the primary key values in another table. This constraint maintains the consistency and accuracy of relationships between tables, preventing orphaned or invalid foreign key references.
How does data partitioning contribute to database performance?
- Enhances query performance
- Improves data security
- Reduces storage space
- Simplifies data modeling
Data partitioning contributes to database performance by enhancing query performance. It involves dividing large tables into smaller, more manageable pieces, allowing the database system to access and process only the relevant partitions, resulting in faster query execution.
What does denormalization involve in relational schema design?
- Applying normalization to eliminate duplicates
- Ensuring data consistency through constraints
- Introducing redundancy for performance optimization
- Reducing redundancy and improving efficiency
Denormalization in relational schema design involves intentionally introducing redundancy for performance optimization. This technique is employed to simplify queries and enhance read performance, especially in scenarios where read operations significantly outnumber write operations.