Using the installation script, you are prompted for the different packages that should be installed, as well as their directory. You should install all the packages included with the Adabas-D CD-ROM for a complete Adabas-D system, with the exception of any language you don’t want (Adabas-D is usually distributed with both English and German documentation and command sets). There are usually four components to the Personal Edition system, which is the version most users will want:

•  adabas-6.1PE. The kernel and all binary and configuration files (approximately 46MB).

•  adabas-mydb. The sample database with a diashow of German railways (approximately 74MB).

•  adabas-docEN. English documentation (105MB).

•  adabas-dokDE. German documentation (79MB).

Before Adabas-D can be started, two shell variables must be set for each user account that will have access to the database package. The shell variables are

•  DBROOT. The installation directory (/opt/adabas-d, for example).

•  PATH. Adds DBROOT to the usual shell path (usually set as $DBROOT/bin:$PATH).

The adabas-mydb package installed earlier is a complete tutorial and sample database that details the German railway system (which is interesting by itself if you like trains!). You can run this example through an X session to see what Adabas-D is capable of. To start the demo, start X (after you have set the required shell variables) and issue the command:

panel

The user name to enter is “control,” and the password is “control.” The database name is “MYDB.” Click the Connect button in the window and wait for the traffic light signal that appears to change to green. The database contains some pictures of the German railways. To see these pictures, start the “fotos” program in an X terminal, use the username “demo,” the password “demo,” and the same database name as before (“MYDB”). Adabas-D should be up and running now. If there are any problems, make sure the environment variables are set properly and that the installation didn’t generate any error messages.

Documentation for the Adabas-D system is in the doc directory under the Adabas-D root directory (such as /opt/adabas-d/doc).

LINCKS

LINCKS is an object-oriented database management system. LINCKS is a good system if you intend to use it on a network and share data via RPC calls. You need to have some experience with networks, as well as an existing network to fully benefit from this package. This package is not for a single node system just because it would be an overkill for such a platform.

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Note:  
You can get LINCKS from sunsite.unc.edu in the /pub/linux/apps/database/ lincks directory.

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LINCKS is based on an append-only object-oriented structure. Objects are derived from other objects. Links can be set between objects to define relationships. You define views to an object. A view is used to specify how the data in the object is presented to a user. Multiple views can exist for the same object. Views can be inherited.

The main interface is xlincks program. Using commands similar to emacs, you can interactively browse through databases. The interface resembles the hypertext functions of a Web page. You click on a highlighted item, and the program leads to a page with more information about the topic.

Help is available in two forms: context sensitive or as a browseable database. The help file is always a button away—to access help, simply press the Help button. The contents of the help file are well organized and are a good starting place to learn about LINCKS. The manual is also available in PostScript from the sunsite archives.

LINCKS comes with a few programs in its distribution package. You can create new databases using the dbroot command. To prune databases of unreferenced objects, use the cutoff command. The main server for the application is the netserv program, which fires off a dbs process for each connected client.

Other Database Products

Of course, the xBase tools we’ve looked at are not the only databases available for Linux. There are a lot of non–dBASE-compatible tools out there. We can take a quick overview of some other database management systems for Linux. Most of these are free and can be found on the Internet.

•  mbase v5.0 is a relational database system originally written for the Amiga and ported to other platforms. It uses a language format similar to C to do the database programming. To compile using mbase, you need ncurses and time. There are several problems with the Makefile that may require manual editing on your part. If you really want cheap, C-like access to a DBMS, you can use this package. Otherwise, get FlagShip or dbMan because they are more stable and mature.

•  onyx is a database prototype program based on a language format such as C. The make config command starts the process and a series of questions pop up. Answering all these questions results in configuring the database properly for Linux.

•  DBF is an xBase manipulation package and is a collection of utility programs that manipulate dbf files. Some of the utilities, such as dbfadd, add a record or layer of information in the database. dbflist lists the records in the database; dbft lists the structure of each database and its items.

•  typhoon is yet another RDBMS. The most notable feature of this RDBMS (depending on your point of view) is that it’s entirely like C. The problem is that the product still has to mature before being considered a viable RDBMS.

Summary

FlagShip and dbMan are excellent means of porting existing dBASE and dBASE-compatible programs to Linux where they run without modification in most cases and a lot faster in almost all cases. A version of FlagShip is being developed for X to run under FreeX86 or other Linux-based X versions, and that should be available in 1997. For now, though, the demo version of FlagShip lets xBase developers continue to work with their database system under Linux. The commercial product, with its hefty 1,500-page documentation, is $199 and well worth it for developers. dbMan is a logical alternative for those who don’t need FlagShip’s compiler features and extended capabilities.