A Derby database contains dictionary objects such as tables, columns, indexes, and jar files. A Derby database can also store its own configuration information.

• The database directory
  A Derby database is stored in files that live in a directory of the same name as the database. Database directories typically live in system directories.
• Creating, dropping, and backing up databases
  You create new databases and access existing ones by specifying attributes to the Derby connection URL.
• Single database shutdown
  An application can shut down a single database within a Derby system and leave the rest of the system running.
• Storage and recovery
  A Derby database (unless it is an in-memory database) provides persistent storage and recovery. Derby ensures that all committed transactions are durable, even if the system fails, through the use of a database transaction log.
• Log on separate device
  You can put a database's log on a separate device when you create it.
• Database pages
  Derby tables and indexes, known as conglomerates, consist of two or more pages.
• Database-wide properties
  You can set many Derby properties as database-level properties. When set in this way, they are stored in the database and "travel" with the database unless overridden by a system property.
• Derby database limitations
  Derby databases have a few limitations.