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DB/C DX, DATABUS, and PL/B Overview

DB/C DX is a program development tool for the DATABUS programming language.

DB/C DX includes the compiler, the run-time executive and eighteen utilities. The utilities provide functions such as file management, file sorting, file indexing, library management, source file editing and more. DB/C DX is available for a variety of different computer operating systems including Windows XP through Win7 based personal computers, LINUX, most UNIX computer systems, and Apple Mac OS X.

What is DATABUS?
DATABUS is a high level computer language designed for writing business oriented applications. In some respects DATABUS is like COBOL, although DATABUS contains several sophisticated features that are not available in COBOL or in other business languages. DATABUS is used to create highly interactive applications that contain friendly user interfaces. DATABUS is also used to create processing programs that deal with the large data files typically found in business applications.

DATABUS was created by Datapoint Corporation in the early 1970s. Until 1981, Datapoint was the only company providing a DATABUS compiler. Since then, at least six other companies have written and are currently marketing compilers for the DATABUS language.

DATABUS was accepted as an ANSI standard in December 1994. In the process it was given the name PL/B because Datapoint refused to relinquish its trademark on the name DATABUS. People still generally refer to it as DATABUS.

Why use DATABUS?
DATABUS has always been a language that is easy to learn and use. Other languages that offer these benefits typically have few operations and limit the functions available to the programmer. DATABUS is easy to use because of its structure and readability.

The syntax is English-like and there are no cryptic characters to remember. But don't let this fool you—DATABUS contains over 125 separate operations (called verbs) that provide the competent programmer with an arsenal of functions. Here is an example of typical DATABUS code:

.
. THIS PL/B CODE FRAGMENT WILL LOOK UP THE
. TELEPHONE NUMBER OF AN EMPLOYEE BY EMPLOYEE NUMBER
.
   LOOP
     KEYIN "ENTER AN EMPLOYEE NUMBER: ", EMPNUM
     STOP IF F3
     READ EMPLOYEE, EMPNUM; NAME, TELNUM
     IF OVER
       BEEP
       DISPLAY "EMPLOYEE NUMBER NOT ON FILE"
     ELSE
       DISPLAY "NAME: ", NAME, "TELEPHONE: ", TELNUM
     ENDIF
   REPEAT

Many business languages in use today were really designed for mainframe batch operation or single user PC operation. The aspect of multiple users accessing common files interactively is only an add-on in these languages. However, DATABUS was designed from the beginning to be run in an interactive, multi-user environment.

The functions available to the programmer for screen display and keyboard handling are excellent. The data access and locking mechanisms are time tested and stand up well in a high performance, heavy usage operation.

DATABUS is also a fine complement to SQL based database systems. Even though most SQL database systems come with a built-in 4GL, many database applications are still being written in a third generation language. The reasons for this vary, but the bottom line is that a 4GL is not capable of providing a programmer with all the functions that a third generation language provides. When the choice comes down to COBOL, C/C++, Java, VB, or DATABUS, many developers are choosing DATABUS.

Here are some of the many reasons why development in DATABUS is superior:

1. Compilation is extremely fast and there is no link step at all.

2. Debugging a DATABUS program is made much easier by the fact that the language is completely closed. All variables are automatically initialized. A numeric variable cannot contain or be assigned an invalid value. There are no pointers that can be pointing into odd places causing subtle and hard to find bugs. There is no data overlaying which can cause data type mismatches. A DATABUS program cannot cause a memory dump - it's just not possible.

3. In addition to an indexed sequential access method, DATABUS provides another access method called the associative index method. Commonly called AIM, this access method allows context-free key searches into data files. For example, in a parts inventory file, it is possible to retreive all records that contain the word "BOLT" anywhere in the description field. The word may be in upper case, lower case or mixed case. The programmer does not need to pre-progam or extract keywords before the lookup - the AIM search method does it all for him.

4. The keyboard input and screen display verbs provide many more functions than corresponding functions in other languages. Pop up window display is almost trivial to implement. Display attributes such as reverse video, underline, blink, and colors are specified in the DISPLAY verb with short, easy to remember codes. The programmer does not have to look at a different section of program (or even at a separate screen map module as in certain other languages) to figure out what is displayed on the screen. It's all right in the program.

Why should I choose DB/C?
DB/C DX implements all aspects of the PL/B standard. DB/C DX also includes utilities that provide all of the necessary operating system level functions used in conjunction with DATABUS programs.

The most important feature to understand about DB/C DX is its portability. No other language in existence today provides better portability than DB/C DX. The reason we can make this statement is simple:

Programs compiled under DB/C DX can be run on any supported computer without recompilation.

This level of portability provides you with an unprecedented ability to run your applications software on almost any computer you choose - with the guarantee that it will run correctly without any program changes or other programmer intervention.

If you currently have DATABUS programs written for Datapoint's RMS DATABUS or DOS DATASHARE systems, porting to DB/C DX is quick and simple. Certain features of DB/C make the conversion from the Datapoint dialects of DATABUS easier.

Using DB/C DX, development and testing of new or existing DATABUS programs is noticeably enhanced from what is available with other DATABUS compilers. Compilation speed is typically hundreds of thousands of lines per minute. Coupled with the fact that there is no link step, total compilation time is faster than any other general-use compiled language in existence. An entire system such as an order entry system consisting of 50 programs can be compiled in less than a minute on a Pentium based computer. On more expensive UNIX systems, compilation is even faster.

Is choosing DB/C DX prudent?
Yes. DB/C DX has been a very successful choice for many companies. Version 1 was first installed in 1983 on single user IBM PCs. Since then many additional major upgrades have been released that have improved DB/C DX in numerous ways. DB/C DX is currently installed in over 3000 companies in 30 countries. Here is a partial list of some of the more well known customers:

Boeing Corp.
Chase Manhatten Bank
Computer Sciences Corporation
Credit Lyonnais Bank
EDS
Guardian Industries
Holiday Inn
Hyatt Hotels
Lincoln Center for Performing Arts
Manufacturer's Hanover Bank
Marathon Oil Company
Nissan Motor Corporation
Proctor & Gamble
Royal Caribbean Cruise Lines
Scott Paper Company
State of California
U.S. Army
USCO Distribution
Volvo