• Simple and efficient Key-value lookup
• SQL++ querying (previously called “N1QL”)
• Full-Text Search
• Analytics (also with SQL++)
• Mobile sync

Couchbase is a multi-model database: you can start with simple-to-understand key-value operations and progress to SQL++ or Full-Text Search when you need those services. It’s all the same pool of data: no need to bolt on extra tools or integrations. It’s all in the box with Couchbase.

Couchbase isn’t the only NoSQL database exploring SQL. it is worth nothing that Microsoft’s CosmosDB and Amazon’s PartiQL also offer some degree of SQL compatibility (albeit not as full-featured as Couchbase’s SQL++). But the adoption of SQL++ as a standard makes for a more natural transition from legacy/relational databases.

https://www.amazon.com/SQL-Users-Tutorial-Don-Chamberlin/dp/0692184503

Also, I will recommend a resource for further research on this topic: SQL++ for SQL Users, This is a book by one of the inventors of SQL, Don Chamberlain (also available for free download, courtesy of Couchbase).

NoSQL has a Difficult Learning curve

With all these ways to interact with data, it must be complicated. Mongo specifically calls out Couchbase: “this growth in functionality comes at a cost: an explosion in complexity for developers“.

However, you do not need to use all these tools right away. You can start with a familiar SQL query or a simple-to-use key-value API. Later, when your use case requires it, you can advance to more complex SQL++ for flexibility, sub-document API for performance,or a full-text search index for efficient searching.

When it comes to issues with learning NoSQL databases, they’ve been all but eliminated when it comes to Couchbase compared to others. Couchbase has constantly been working to make the developer experience smoother, such as the following:

• Couchbase Playground – a completely free, in-browser experience to modify and execute code samples for all SDKs (Java, Node.js, Python, .NET, PHP, Ruby, Scala, Go, C++, and Kotlin).
  
• Couchbase Capella – a fully managed and hosted Database-as-a-Service (DBaaS) to reduce the overhead and time needed to perform administrative tasks. Just get a connection string and start coding.

And, I’ll again mention SQL++ because SQL is the most popular language in the world for working with data. Consider this side-by-side comparison of a SQL++ query and a Mongo query, which both return the same result:

The fact still remains that not only is the SQL example given above more concise and arguably more readable than the proprietary Mongo query language, but it’s also a standard language understood by a large percentage of developers and software professionals.

Couchbase has invested in the SQL standard for years, and in a challenging hiring market, SQL can be a skill that makes the NoSQL learning curve much less steep.

NoSQL Like of Couchbase is almost or just like a Key-Value Store

The fact remains that the core of Couchbase is a very efficient, memory-first key-value engine. This has been the case from day 1. But Couchbase has built on that core engine, and it became one of the first “multi-model” NoSQL databases.

What is the meaning of Multi-Model NoSQL Database?

Multi-model means that a NoSQL Database like Couchbase provides multiple ways to interact with a single pool of data:

• Key-value: read/write data via a “key” lookup. Extremely fast, especially with a memory-first architecture, and great for simplicity.
  
• SQL++: This is the world’s most popular language for querying data, providing flexibility and an industry standard.
• Full-text Search: This is also known as “FTS”, provides a text “search engine” for data, as well as geography-based searches. 
• Analytics: Querying data with complex, adhoc SQL++ queries, with workload ioslation.
• Eventing: JavaScript functions that can respond to data change events.
• Mobile: Offline-first, automatic synchronization of data to mobile devices, edge devices, and even desktop software.

With the above facts about Couchbase, it is highly inaccurate to say that Couchbase is only for key-value use cases.

Couchbase doesn’t have Lucene search

This is a entirely a bizarre point of comparison that MongoDB calls out specifically about Couchbase.

Couchbase has a built-in Full Text Search engine powered by the popular open-source library called Bleve (which was written using Go). It’s not Lucene, but it is still a full-featured library capable of stemming, language awareness, relevancy scoring, geospatial search, fuzziness, etc.

Bleve is built right into Couchbase, and does not require any additional connectors or integrations: just create an index and start searching. The following video shows just how simple yet powerful this solution can be.