Java DB

No, Java DB is a relational database management system (RDBMS). Data is stored and queried via SQL or JDBC. Like other RDBMSs, Java DB can also be accessed through a persistence layer such as JPA, Hibernate, or JDO.

No, Java DB is Sun's supported version of Apache Derby and contains the same binaries as Apache Derby.

Yes, support is available from Sun. You can also contact the Apache Derby user community with questions and bug reports.

Absolutely. Java DB is a multi-user database engine and supports concurrent users.

You can download Java DB from the Downloads page on this site. Java DB is also bundled as part of Sun's JDK 6 as well as in GlassFish.

The Java DB download page has installation instructions. The Apache Derby Tutorial is a good place to begin. Additional resources are listed in the Reference section of this site.

Java DB supports all SQL standard numeric and character data types, as detailed at SQL-99 and SQL-2003 features including data types are mapped to Derby, sections E011 and E021. Support for the BOOLEAN data type is under discussion for a future release.

Yes, Java DB supports almost all SQL92 features. You can find details in the section of the Derby Reference Manual titled "Derby support for SQL-92 features."

Yes, see the Derby SQL Routines wiki page for information on how to implement procedures and function in Java and how to invoke them.

Java DB supports subqueries in WHERE clause, FROM clause, IN predicate, and quantified comparison predicate, but does not currently support updatable queries with subqueries.

Yes, Java DB supports upper, lower, concat, substring, like, length, trim; see SQL-99 and SQL-2003 features including data types are mapped to Derby, section E021.

Yes, Java DB provides special functions that allow you to extract the year, month, day, hour, minute, and second from a DATE, TIME, or TIMESTAMP value. The returned values are large integers, so you can perform arithmetic operations on them.

Yes, Java DB supports date/time arithmetic through use of the functions TIMESTAMPADD and TIMESTAMPDIFF on a TIMESTAMP value.

Java DB supports the SQL standard aggregate functions: COUNT, MIN, MAX, AVG, and SUM.

Java DB does not currently support this feature, but ROW_NUMBER is currently under development.

Beginning with version 10.2.2.0, Java DB supports JDBC 4.0. Earlier versions support JDBC 3.0.

Yes, Java DB supports these features.

Yes, Java DB provides a full JDBC metadata API implementation (java.sql.DatabaseMetaData).

Yes, Java DB has XA support.

Yes, Java DB supports allows this.

Java DB stores each base table and each index in a single file, so the data size limit is the file size limit of the JVM and OS on which it runs. Derby is coded against the Java 64 bit interfaces to access these files, so internally the maximum table size is approximately 2**64. The number of tables is only limited by the 64 bit length of table identifiers, for an approximate limit of 2**64 total tables. In practice, system resources such as disk space are a more likely source of size limitations. Java DB is tested on a database using over 350 GB of raw disk space with tables containing over 500 million tuples.

The maximum size of a CLOB or BLOB stored in Java DB is 2 GB.

Java DB runs on any platform with a certified JVM. It is tested on wide variety of platforms (see the 10.3 platform testing wiki for details).

The interactive SQL scripting tool provided with Derby, ij, can be used for backup and administration tasks. Currently, Java DB does not include a GUI tool for administration, but there is interest for it in the community, and may be developed in the future. There are open source and commercial GUI tools that support Derby, such as SQuirreL SQL Client. These work well for most users, given Derby's commitment to ease of use.

On many platforms, including Windows and Linux, the disk write cache is enabled by default. This improves disk performance, but can result in data loss or corruption in case of power outage or equipment failure. For more information, please read "The story of the write cache and half a worm."

Yes. For help, see Using JPOX JDO with Derby, Initializing Embedded Derby using JPA, and the HibernateHelp wiki pages.

Java DB can be run with the following Java ME technologies: CDC 1.1, Foundation Profile 1.1, JDBC Optional Package for CDC/Foundation Profile (JSR169). See the JavaMESupport wiki page for more information.

There is currently no built-in clustering support in Java DB. Sequoia is an open source, Apache licensed, clustering solution that works with Java DB.

SQL identifiers containing special characters or identifiers that you wish to be case-sensitive must be enclosed in double quotes. Unquoted identifiers will be case insensitive. See Capitalization and special characters in the Derby Reference Manual for more information.

The Java DB Performance presentation gives an overview of how to configure Java DB to achieve optimal performance while being able to handle failure scenarios without losing data. The PerformanceDiagnosisTips wiki page shows how to investigate performance issues that might occur between Derby releases.