ANSI/ISO standard SQL
- Transactions, isolation levels, row-level locking
- Subselects, views, relational constraints
- Triggers, stored procedures, user-defined functions
Ease of use
- Small footprint: 4 MB JAR file + JVM (one JVM for database, one JVM for network server)
- No or low administration effort required
- SQL interfaces for common tasks like backup
Security
- Authentication (LDAP, custom, built-in)
- Database encryption
Performance
- 200 transactions / second on an untuned system
- 20-30 concurrent users with connection pooling