What are the four main categories of NoSQL databases?

• Key-value, document, column, graph.

• Key-value, document, common, graph.

• Key-value, relational, column, graph.

• Key-value, distributed, column, graph.

Answer explanation

The correct answer is 'Key-value, document, column, graph' as these are the four main categories of NoSQL databases. The other options include incorrect terms like 'common' and 'relational', which do not fit the NoSQL classification.

What is the name of the fully managed service model that many NoSQL databases now leverage?

• Platform as a service (PaaS).

• Software as a service (SaaS).

• Network as a service (NaaS).

• Database as a service (DBaaS).

Answer explanation

The correct answer is Database as a service (DBaaS), which is a fully managed service model that allows users to access and manage NoSQL databases without the need for physical hardware or complex software management.

What is the most common trait among all NoSQL databases?

• All NoSQL databases are open source.

• All NoSQL databases are non-relational.

• All NoSQL databases are relational.

• All NoSQL databases are document-based.

Answer explanation

The most common trait among all NoSQL databases is that they are non-relational. This distinguishes them from traditional relational databases, allowing for more flexible data models and scalability.

Which category of NoSQL database can be adversely affected (mediocre performance) by sharding?

• Graph NoSQL databases.

• Document-based NoSQL databases.

• Column-based NoSQL databases.

• Key-value NoSQL databases.

Answer explanation

Graph NoSQL databases can suffer from mediocre performance when sharded because their data is highly interconnected. Sharding can complicate queries that require traversing relationships, leading to inefficiencies.

Which use case is a good choice for a document type NoSQL database?

• The data naturally falls into a normalized tabular model.

• Online blogging.

• When you require ACID transactions.

• Aggregate-oriented design.

Answer explanation

Online blogging is a good use case for a document type NoSQL database because it allows for flexible data structures, accommodating various content types and formats without the constraints of a normalized tabular model.

What is a characteristic of column-based NoSQL databases?

• Rows in column families share a common key or identifier.

• Columns are grouped together in families because they are often accessed individually.

• Rows in column families are required to share the same columns.

• Rows in column families can share all, a subset, or none of the columns.

Answer explanation

In column-based NoSQL databases, rows in column families can share all, a subset, or none of the columns, allowing for flexible data modeling. This characteristic distinguishes them from traditional relational databases.

What requirement does the BASE model support?

• Immediate consistency

• Isolated consistency

• Atomic consistency

• Eventual consistency

Answer explanation

The BASE model supports eventual consistency, which allows for temporary inconsistencies in a distributed system, ensuring that all updates will propagate and eventually all nodes will reflect the same state.

What is the best way to describe the partition tolerance characteristic of the CAP theorem?

• Provides guarantees for both strong consistency and high availability

• Ensures data consistency even when a partition occurs

• The system continues to operate despite data loss or network failures.

• The database is highly available.

Answer explanation

The correct choice highlights that partition tolerance means the system remains operational despite network failures or data loss, which is a key aspect of the CAP theorem.

Which industry will almost exclusively use ACID databases?

• Marketing consultants

• E-commerce

• Financial institutions

• Online social networks

Answer explanation

Financial institutions require strict data integrity and consistency, making ACID (Atomicity, Consistency, Isolation, Durability) databases essential for transactions, unlike other industries that may prioritize flexibility over strict compliance.

Which of the following is a key advantage of NoSQL databases over traditional relational databases?

• • Horizontal scalability.

• • Strict schema enforcement.

• • Strong ACID transactions.

• • Dependence on SQL for queries.

Answer explanation

Horizontal scalability is a key advantage of NoSQL databases, allowing them to handle large volumes of data across distributed systems. In contrast, traditional relational databases often struggle with scaling horizontally.