HSQLDB vs VelocityDB: What are the differences?

Developers describe HSQLDB as "Leading SQL relational database software written in Java". It offers a small, fast multi-threaded and transactional database engine with in-memory and disk-based tables and supports embedded and server modes. It includes a powerful command line SQL tool and simple GUI query tools. On the other hand, VelocityDB is detailed as "A NoSQL Object Database, extended as Graph Database is VelocityGraph". It is a C# .NET NoSQL Object Database that can be Embedded/Distributed, extended as Graph Database is VelocityGraph. It supports both embedded and distributed deployments.

HSQLDB and VelocityDB can be categorized as "Databases" tools.

Some of the features offered by HSQLDB are:

• Original code, based on in-depth study of database theory and the SQL Standard
• Extensive syntax compatibility modes for porting from other database systems
• The fastest overall open-source SQL implementation for small and medium sized databases

On the other hand, VelocityDB provides the following key features:

• Acid Transactional
• Android
• Any CPU (32bit/64bit)

HSQLDB is an open source tool with 16 GitHub stars and 5 GitHub forks. Here's a link to HSQLDB's open source repository on GitHub.