Practice 20 NoSQL Databases multiple-choice questions designed for CDAC CCAT exam preparation. Click "Show Answer" to reveal the correct option with detailed explanation.
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Correct Answer: B — Not only SQL
NoSQL means "Not only SQL" - databases that provide mechanisms other than traditional relational models.
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Correct Answer: B — Document-oriented database
MongoDB stores data as flexible JSON-like documents (BSON), making it a document-oriented database.
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Correct Answer: B — In-memory key-value store/cache
Redis is an in-memory key-value store, often used for caching, sessions, and real-time analytics.
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Correct Answer: B — High write throughput and availability
Cassandra is designed for high write throughput, high availability, and linear scalability.
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Correct Answer: C — Graph database
Neo4j is a graph database optimized for storing and querying highly connected data.
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Correct Answer: C — Few NoSQL databases, mostly RDBMS
ACID is traditionally an RDBMS strength. Most NoSQL databases prioritize availability over strict ACID.
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Correct Answer: A — Basic Availability, Soft state, Eventual consistency
BASE: Basically Available, Soft state, Eventual consistency - NoSQL alternative to ACID.
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Correct Answer: C — Key-value store
Key-value stores are ideal for session data and user profiles - fast lookup by key.
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Correct Answer: B — As columns grouped into families
Column family databases store data in columns grouped into column families, optimizing for specific query patterns.
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Correct Answer: B — Data will become consistent given enough time
Eventual consistency guarantees that, given no new updates, all replicas will eventually converge to the same value.
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Correct Answer: B — Horizontally partitions data across nodes
Sharding distributes data horizontally across multiple nodes based on a shard key.
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Correct Answer: B — MapReduce views and Mango queries
CouchDB uses MapReduce views for complex queries and Mango for declarative JSON queries.
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Correct Answer: C — Neo4j
Graph databases like Neo4j excel at traversing relationships, perfect for social networks.
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Correct Answer: B — A table in RDBMS
MongoDB collections are analogous to RDBMS tables - they group related documents.
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Correct Answer: B — Amazon
DynamoDB is Amazon's fully managed NoSQL database service on AWS.
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Correct Answer: B — Automatically expires keys after specified time
TTL automatically deletes keys after a specified duration - useful for caching and session management.
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Correct Answer: B — Flexible schema that can vary between documents
Schemaless allows documents in the same collection to have different fields and structures.
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Correct Answer: B — Durability by logging before writing
WAL logs changes before applying them to data files, ensuring durability in case of crashes.
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Correct Answer: B — PostgreSQL
PostgreSQL is a traditional relational database (RDBMS), not a NoSQL database.
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Correct Answer: B — Minimum nodes that must agree for operation success
Quorum defines the minimum number of nodes that must acknowledge an operation for it to succeed.