ArangoDB vs CouchDB: What are the differences?

Introduction:

ArangoDB and CouchDB are both NoSQL databases that are designed to handle large amounts of data and provide high performance. However, there are key differences between the two that make them suitable for different use cases.

1. Data Model:

ArangoDB is a multi-model database, which means it supports multiple data models including document, graph, and key-value. It allows users to store and manage structured, semi-structured, and unstructured data in a single database. On the other hand, CouchDB is a document-oriented database that stores data in JSON format. It is specifically designed for handling semi-structured data and provides a simple and flexible storage model.

2. Query Language:

ArangoDB uses a query language called AQL (ArangoDB Query Language) for performing complex queries and data manipulation. AQL is a powerful language that supports a wide range of operations and allows users to combine document, graph, and key-value operations in a single query. In contrast, CouchDB uses map-reduce functions for querying and data transformation. Map-reduce allows users to define custom functions for extracting and processing data from documents.

3. Replication and Scalability:

ArangoDB supports both master-slave and active-passive replication, which allows users to create replicas of their data for fault tolerance and high availability. It also provides support for sharding, which enables horizontal scalability by distributing the data across multiple servers. On the other hand, CouchDB supports master-master replication, where the databases can sync with each other bidirectionally. This allows for decentralized data replication and enables offline access to data. However, CouchDB does not natively support sharding for horizontal scalability.

4. Licensing:

ArangoDB is licensed under the Apache 2.0 license, which allows users to freely download, use, and modify the software. It also allows for commercial use. CouchDB, on the other hand, is licensed under the Apache License 2.0 as well, but it has an additional term called the "Commons Clause". The Commons Clause restricts the commercial use of CouchDB and prohibits users from selling CouchDB as a service without obtaining a separate license.

5. Indexing:

ArangoDB supports various types of indexing including primary, secondary, hash, skiplist, and fulltext indexes. This allows for efficient searching and querying of data based on different criteria. CouchDB, on the other hand, only supports simple B-tree indexes on fields within the documents. While this is sufficient for many use cases, it may limit the flexibility and performance of complex queries.

6. Community and Ecosystem:

ArangoDB has a strong and active community with regular updates and contributions from the user community. It has a growing ecosystem of libraries, tools, and extensions that enhance its functionality. CouchDB also has an active community, but it is relatively smaller compared to ArangoDB. It has a mature ecosystem with various plugins and extensions, but it may not have as many options as ArangoDB.

In Summary, ArangoDB is a multi-model database with support for various data models, a powerful query language, and extensive indexing capabilities. It also provides advanced replication and scalability options. CouchDB, on the other hand, is a document-oriented database with a simple storage model, map-reduce queries, and decentralized replication. While both databases have their strengths, the choice between them depends on the specific use case and requirements.