Appendix B
Database Software for Linux

The following lists some of the database software that is available for Linux. We hope it will help you in your search for the right software for your Linux system.

SQL Packages

The following SQL-based packages run under Linux. This list includes all the commercial database packages that are sold for Linux.

Empress

Empress is the largest, most complete relational-database package available for Linux. This professional system is manufactured by Empress Software, Inc., of Markham, Ontario, Canada. The Empress package includes the following:

•  ANSI-compliant SQL engine

•  ODBC server and ODBC drivers for both Windows and UNIX

•  Fourth-general language (4GL) for application development

•  Report writer

•  Motif-based GUI application builder

•  HTML toolkit

•  UNIX-based networking for distributed databases

The package comes with an impressive set of manuals. Depending upon the version of Empress, these either come printed and bound, or as PostScript files that you must print yourself (or view with ghostscript).

Under Linux, Empress is available for both a.out and elf systems.

Empress is designed to handle large binary objects—images, sound bites, and the like—particularly well. This, plus the fact that it supports an HTML library for interacting directly with the database, makes it particularly interesting as a front end for a Web site.

Empress is packaged in a number of different ways. An inexpensive personal edition is available; this edition does not support networking or multiple simultaneousconnections, but it does include the engine, 4GL, report writer, GUI application builder and the HTML toolkit.

For information on Empress, see URL:

Yard

Yard is a commercial relational database package that is manufactured by Yard-Software, Ltd., of Cologne, Germany. The Yard package consists of the following:

•  ANSI-compliant SQL server, which supports a binary large objects (BLOBs)

•  Network-access daemon

•  ESQL preprocessor

•  Motif interface for database access

As of this writing, ODBC and JDBC drivers are not available for Yard.

Yard comes with all of the features one would expect from a professional-quality package, including an excellent manual.

A private edition of Yard is available for free. This edition does not support networking, and databases cannot exceed five megabytes. For details on Yard, and to download a copy of the personal edition, see URL:

dbix

dbix is a professional relational database package available for Linux and a number of other UNIXes. It offers a robust, reasonably priced package for Linux. It is manufactured by Halcyon Software of Campbell, California.

The dbix package includes an ANSI-compliant SQL engine, and ODBC driver and server libraries. The dbix package is designed to work with Halcyon’s vbix tools, which support Visual Basic scripts under UNIX.

For details, and to download sample editions of vbix, see URL:

CQL++

CQL++ is an ANSI-compliant relational database package that is published by Machine Independent Software, Inc., of Chandler, Arizona. As its name implies, the CQL++ is distributed in the form of C++ source code that you recompile on your Linux system.

CQL++ supports standard ANSI SQL-2. It uses ODBC as its call-level interface; therefore, programs written in ODBC probably will work with CQL++ with few or no modifications.

For information on CQL++, and to download a copy of its free, single-user edition, see URL:

Postgres95

Postgres95 is a freely available relational database package that incorporates many powerful extensions to the classic relational model.

Postgres95 is derived from the Postgres database system developed at the University of California, Berkeley, by Professor Michael Stonebraker. Postgres was the original object-relational database. Its development was halted in 1994, but it forms the basis for the Illustradatabase package. Dr. Stonebraker has since become vice-president of technical development at Informix Software, and is busily merging the Informix and Illustra servers to create the Informix Universal Server, a product that has attracted a great deal of attention in the database world.

The sources for Postgres have also been used as the basis for the Postgres95 project, which is headed by Andrew Yu and Jolly Chen at the University of California, Berkeley. Postgres95 has simplified the original Postgres model, streamlined and speeded up the engine, and (most important) replaced the POSTQUEL query language with SQL.

Postgres95 has implemented a subset of SQL. The most important limitation is that its engine does not support subqueries.

The Postgres95 package includes database engine, libraries, and brief but well-written manual. The programming environment is minimalistic; this is definitely a programmer-friendly environment.

The object-relational extensions that Postgres95 supports are very powerful and very interesting. If you choose to do your database development under a supported, commercial package, you should consider looking at Postgres95, as it offers a good view of the future of database programming.

Postgres95 appears on the disk included with this book. For the latest details on Postgres95, see URL:

OpenLink has released versions of its ODBC clients and servers for Postgres95 running under Linux. Together, the OpenLink drivers plus the Postgres95 database packagecomprise a powerful database environment for Linux. To download free evaluation copies of this software, see URL:

Non-SQL Packages

The following database packages are built around a query language other than SQL. These include most of the large research databases that have come out of universities.

University Ingres

This package is one of the original relational databases. It was developed by Michael Stonebraker at the University of California, Berkeley, and later served as the basis of the Ingres package that is now sold commercially. Its query language, QUEL, is an ancestor of SQL.

Ingres is old technology—it does not support networking, ODBC, or SQL—and it is no longer being actively supported. However, it is a tried-and-true database package that is well designed and is well regarded.

A copy of University Ingres is included on our disk. For details on this package, see URL:

/rdb

/rdb is a relational database package that is published by Revolutionary Software, of Santa Cruz, California. /rdb is unusual in that it uses the UNIX shell as its interface. This package is relational in its design, although it does not claim to be relationally complete.

This package runs on Linux and a wide variety of other platforms. For details, see URL:

Further Information

offers links to a wide range of software packages that run under Linux. Many are freeware or shareware; some are commercial. This site is updated regularly, so you should check it out from time to time.

offers information about using Java under Linux. It also points to mirror sites from which you can download a copy of the latest edition of Sun’s Java Development Kit.

gives links to hundreds of Java applets, many of which use databases in one way or another. Source code is available for many of the applets.

is the gateway to a database that holds information about every free database package available anywhere. Many of these packages are trivial, and not all are available for Linux; but this list is worth perusing to see what groups around the world are doing to develop database software.