Editor: Ted G. LewisSComputer Science Dept.

Oregon State University

Sol w" - B \ v v " @ Corvallis, OR 97331

Software Reviews evaluates operating systems, applications, and utility software in widespread use. Reviewsare not limited to technical descriptions of various packages - the economic andphilosophical aspects ofsoftware systems are also examined. Reviewsfrom readers are welcome, as are comments and opinions.Please send all correspondence to the above address.

dBase III for the IBM PCDavid Rubin, demonstration files and utility programs. DocumentationJet Propulsion Laboratory The fourth was a backup disk. One util- The documentation comes in a well-

Ashton-Tate's dBase III is targeted for ity program converts dBase II data and constructed three-ring binder. Sandwichedevery level of user throughout the spec- command files into dBase III. System betee theers are installation direc-trum of experience and application com- Disk I was copy-protected with Prolok, twen te cor areinsttallatnudrplexity. It is intended to accommodate but the other system disk and the utili- tions, a few late corrections to the manual,users who are new or advanced in database ties disk were unprotected. tutorial a reference manual, a glossarymanagement. Although it is copy-protected, dBase and an index.Heading the advanced level are the ver- III can be installed on a two-megabyte Ashton-Tate has provided an extra

tical application developers, the people hard disk through an installation rou- ingredient in this documentation sand-who design and perhaps sell complete tine that resides both on System Disk 1 wich for dBase II users: a guide for theuser-oriented packages written in the and on the backup disk. Once installed transition from dBase II to dBase III.dBase language. Many of these users have from a floppy onto a hard disk, the pro- This "IdBase Bridge" section, written byprobably cut their teeth on dBase II or gram can't be installed elsewhere. How- dBase II guru Adam Green, discusseson a mainframe database management ever, there is an uninstall option to transfer and illustrates the differences betweensystem. They will have little difficulty dBase III back to a floppy so it can be the two versions.mastering dBase III and will enjoy the installed on another hard disk. The installation instructions are sim-many improvements over its predecessor, Although a hard disk is not required ple and direct. They include directions

dBase III lets you quickl asil and to run dBase III, a user without one for installing Ashton-Tate's dBase screendBase III lets you quickly, easily, and might encounter fairly troublesome han- editor and a utility to generate and editselectively generate, rearrange, manipu- dicaps. If you have only floppy drives, report formats and text fields.late, modify, combine, update, review, yums ev.Sse ik2i rvextract from, and do calculations on you must leave. System Disk 2 in drive Atens of thousands of numerical and text each session. Only drive B can access Excellent tutorial. The tutorial is excel-database entriesa data, command, and other files. This lent. Well-written and well-organized, it

If necessary, you can perform any or can increase disk swapping by two times covers most of the system's commandsIf necessary, you can perform any o or more. and functions, and introduces someall of these actions using data from as rudimentar pormintechniqe

many as 10 related files at once. Fur- More important, it also means that rudilmentary programming techr ques.. :. . . . . > ~~Its style, content, and pace are suited forthermore, you can do everything with many dBase II applications designed for naive users. It takes you from a simplejust a few keystrokes once you have a two-drive PC will likely require exten-mastered the intricacies of the dBase III sive modification before they can be explanation of database files to how tocommand files. converted to dBase III. With a hard write your own command files.The evaluation package I received disk, System Disk 2's programs are put But while the tutorial iS excellent, a

contained four disks. Two system disks on drive C - and these problems dis- m stly needhelplfomrsmeoncontained the program files. A third had appear. mostakely need help from someone

* ~~~~~~~~~else:a users group, a database-orieritedperiodical, an advanced training semi-nar, or one of the recent books ondBase III.The removable quick-reference guide

can be folded so it stands freely on adesk, taking an area of only three by sixinches. The reference manual complementsthe tutorial with explanatory descrip-tions of all the file types, commands,and functions. The glossary is a usefuladjunct for new users, while the indexappears to be extensive and accurate.

Thorough enough? The only question IA - A -0 had about the documentation was whether

i was thorough enough. Should Ashton-

74 IEEE SOFTWARE

Tate provide enough information in its The commands fall into eight areas: Each user-interface command is moretutorial and reference manual to cover program and data creation, data display capable. For example, while appending,the full extent of the program's many and editing, record pointer positioning, you may also edit previous records incapabilities? file manipulation, memory variable the file. In browse, you can now lockSome of dBase III's advanced capa- manipulation, command file control, fields on the left side of the screen so

bilities are mentioned only casually, control parameter modification, and they don't disappear when you scrollsometimes in only one or two descrip- peripheral device control. horizontally. You can also append andtive sentences - without even a hint on The functions fall into five areas: date insert records while browsing. Anhow or why they might be used. For and time, character manipulation, mathe- options menu permits rapid movementexample, the tutorial shows how a memo matical operations, character and to other records in the file, and menufield is generated and how it can be numeric conversions, and specialized help is available for the create/modifyedited. But that's all. What do you do tests. report commands.with the memo field after that? The The program boasts a new group ofanswer is left to your imagination and date-manipulation functions and a newexperimentation. date data type to go with them. Dates Innovations. Among the program'sYou might expect omission of such are treated as numbers rather than strings, many innovations is the procedure file.

features in a guide to a general program- so arithmetic can be performed on them These files may contain as many as 32ming language or operating system. But, to extract new information. For exam- command routines that can be called upas its advertisements make clear, dBase ple, dates can now be subtracted to yield individually by command files or byIII is oriented to the end user. It should the number of days between them. dBase other procedures with-a do command.have more details and examples than a II could have done this only with exten- Once opened, any routine in a proce-typical manual. sive, complex programming. dure can be called without opening aCh dBase III permits sorts on as many as new file. Procedure files also increase

Characteristics seven key fields. Sorts are about four the speed with which command sets canThe new dBase accommodates data times faster than on dBase II. Most be called as subroutines.

files that have 1 billion records (2 giga- other operations are between two and 20 A related improvement is that databytes). The records can contain 128 times faster. The only thing that seems can now be passed as parameters from afields, with a maximum total of 4000 to be no faster is disk access. For floppy- calling program to variables in the calledcharacters. More significantly for many disk-intensive operations, some of dBase subroutine.applications, you can now have 256 III's speed advantages may be less In a significant change from dBase II,memory variables (6000 bytes) at once impressive. memory variables are no longer global.and 10 open data files. You can simul- All variables are private unless explicitlytaneously open 15 files of all types. User interface. The program has a declared to be public. They exist onlyNumeric accuracy has been improved software interface, called the assistant, while the command file they are named

to 15.9 digits. The largest and smallest that lets a casual user perform many in is open. A variable explicitly declaredspecifiable numbers have been changed tasks after spending only a few hours private in a called program can be writ-to 10E308 and 10ED307, respectively, with the tutorial. This assistant is a hier- ten to without overwriting a variableWhile the field size remains at 254 archical arrangement of menus, prompts, with the same name in a calling pro-

characters, this limitation is of little and help screens. The screens use a few gram. Public variables defined in a call-consequence now because the new memo of the IBM graphics characters for some ing program remain accessible evenfield can hold 512K characters ifproduced flash, but they don't use color. when another program has been called.by an external word processor or 4000 The assistant's first menu lets you The more capable menu- and prompt-characters if produced by the internal enter the six functional environments: assisted full-screen editor lets you createtext editor. A memo field sets up a new file and report format setup, database and print address labels. Other improve-file type with a .DBT extension as an file modification, movement through ments include linking as many as 10auxiiary file to the .DBF data file. You database files, data display and extrac- files, changing display precision, modify-use it instead of a normal field when tion, data copying and reorganization, ing file structures without erasing fileyou want to enter more than 254 char- and DOS and dBase utilities. contents, setting warnings to preventacters. In each environment, the assistant accidental file overwrites, and readingThe program supports DOS 2.0's sub- helps you choose and construct a com- cursor positions to improve menus.

directory paths so that data and command mand. The degree of guidance seems to However, some changes are hard tofiles do not have to be in tho same sub- be keyed to the user's experience. More accept as improvements. For example,directory as the dBase program. It does constraints are offered for the more fun- the set-step-on command no longer per-not support the 8087 math coprocessor, damental operations. For example, if mits keyboard entry, the "correct andbut a third-party vendor is likely to offer there is no data file in use when you retry" prompt is no longer available tothis as an add-on. invoke the assistant, you are forced to edit command errors, and macros can

create or use a file before doing any- longer be used as the condition in a do-Commands and functions. The dBase thing else. while command.

III command set constitutes a full- The regular user interface is much dBase III is conveniently configurablecapability procedural language with more attractive and convenient than to your personal needs. When dBase ismany features found in modern high- dBase II's. Append, edit, change, cre- started, it looks for a text file calledlevel programming languages. It has 35 ate/modify report, browse, and modify CONFIG.DB just as PC-DOS looks forfunctions and more than 100 English- commands all use the same full-screen CONFIG.SYS when it boots up. Bylike commands with hundreds of varia- editor, so functions are invoked the editing CO)NFIG.DB, you can modifytions. Its design encourages (or enforces) same way from command to command. any of 24 default values and the func-good structured programming practices. The invocation is similar to WordStar, tion keys. You can also tell dBase toIt doesn't even have a goto statement to but there are also some annoying differ- automatically begin with a command ortempt you. ences. command file instead of the dot prompt.

March 1986 7

dBase II to III the files is less than 21. The longest file Dataflex and Network Revelation sayhas 74 command lines. The media num- they are suitable for multiuser applica-Converting dBase II files to dBase III ber of command lines is about 17. This tions. They also have a runtime moduleformat is a semiautomatic process using should provide a crude way of estimat- available. And Cosmos advertises an

the dCONVERT EXE file on System Disk ing your conversion time. application generator and application2. How easy a conversion it iS depends compiler for its Network Revelation.on the complexity and design of the One of the most frequent complaintsapplication. about dBase II was the difficulty ofData files convert with user assistance. The competition mastering its language. dBase III allevi-

Command files are another story. The dBase II had virtually no competition ates this shortcoming to some extent.conversion program picks up all the syn- for a long time. When rival packages However, pushing dBase III to thetax and command name changes. It even finally appeared, they hardly made a fringes of its capacity is still a formida-substitutes or suggests more efficient ripple in the sea of sales enjoyed by ble and frustrating task. Microrim,commands in some cases. A reasonable Ashton-Tate. dBase III, on the other whose R:base 5000 has many qualitiesproportion of converted command files hand, has several competitors, each of comparable to dBase III, claims itscan be used just as they are. whom claims to possess all of dBase menu-building utility and its optional

But many files will require logical and III's capabilities and more. query system make language masterystrategic changes to accommodate the Three of the more popular competi- much easier.many changes in how dBase III responds tors are Microrim's R:base 5000, Data dBase III is a welcome advance into commands, to better exploit dBase's Access's Dataflex, and Cosmos's Net- microcomputer database managementnew features, and to rewrite the tortuous work Revelation. Each has its own limi- systems. But its speed in becoming acommand sequences used to circumvent tations and disadvantages, but some of benchmark is due more to the huge suc-dBase II's limitations. the claimed differences between them cess of its predecessor than to its own

It is hard to predict how much effort and dBase III are worth mentioning. superiority. It is intended to appeal toand time a conversion will require. How- dBase III is only for single-user appli- the entire range of potential users, butever, Adam Green provided a bench- cations. It doesn't have passwords or its applicability for the casual user andmark in his "dBase Bridge" portion of file and record protection. If you have a for the current dBase II user can bethe documentation. He said it took him multiuser application, look elsewhere. reasonably questioned.a week to convert the 80 or so program (Ashton-Tate introduced a multiuser ver- Because of the complexity and powerfiles in his two dBase II books. sion of dBase II, but it didn't catch on of its command structure - and because

Presumably, a week means about 40 and has been withdrawn. But Ashton- of the difficulty of conversion fromhours. Most of the programs in the Tate recently announced dBase III Plus, dBase II - it seems most appropriatebooks have extremely simple logic. The a multiuser version that eliminates the for new, dedicated, sophisticated usersaverage number of command lines in dBase III limitations described here.) who have large single-user applications.

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