H2 Database Engine: Open-Source Java Relational DB
H2 Database Engine: An open-source relational database management system written in Java, ideal for testing, prototyping, and small applications.
What is H2 Database Engine?
The H2 Database Engine is an open-source relational database management system written in Java. It can be embedded in Java applications or run in client-server mode, with either TCP or disk-based database files.
Some key features of H2 include:
- Small footprint - The H2 jar file is around 2MB and it has a relatively low memory footprint.
- Support for standard SQL and JDBC APIs - Applications using JDBC can easily switch from other databases like MySQL or PostgreSQL.
- Client-server capabilities - H2 can run in a client-server mode where multiple applications can connect to it.
- In-memory capability - Tables can reside either on disk or in memory depending on need.
- Encryption - Database files can be encrypted using algorithms like AES or SHA-256.
- User authentication - Users can be restricted and granted permissions on different database objects.
- ACID transactions - H2 properly implements transactions, rollbacks, commits etc.
- There are also various options available for backup and recovery, clustering, monitoring etc.
Some common use cases well-suited for H2 include testing, prototyping, small applications and websites. Its lightweight nature, small footprint and in memory capabilities make it very convenient to be embedded into applications.