SPACE 1/SPACE - Library 1 - Volume 1.iso/apps/298/dbman.tut/dbmanrev.txt

Text File | 1989-05-28 | 13KB | 257 lines

                               dBMAN by Versasoft
                       An Initial Review by John C. Leon
                                  May 29, 1986
                             edited August 18, 1986




                     distributed through the H.A.S.T.E. BBS
                  Houston Atari ST Enthusiasts   713-955-9532
            permission granted to distribute unaltered original text


          It is very difficult for me to evaluate a complicated piece of
        software like  this  in a brief "memo" form of review.  I regret
        not having had time to put dBMAN through  all  its  paces before
        reporting to you, but we thought you deserved a quick opinion of
        this relational database program.

          Let's talk a sec about relational  databases.   Those  of  you
        coming straight from the 8-bit Atari world without experience on
        other machines have never seen a  relational  database,  as  the
        8-bit Atari had none  available  for  it!   Products  like  Data
        Perfect and Synfile+ are known as  file  managers.   This  means
        that  they  can only work on one file at a time.  They are  also
        inflexible (tho Data Perfect I consider to be quite powerful) in
        that the built-in functions  are  all  you've  got.   You  can't
        program a data manipulation routine of your own.

          Relational databases are  an  entirely new ballgame.  CP/M and
        MS-DOS users have had dBASE, dBASE compilers like Clipper, RBASE
        5000,  Paradox,  and a host of similar products for  quite  some
        time.  The relational databases have two primary characteristics
        that separate them from the file managers.

          First,  the  capacity   to   work  on  numerous  "open"  files
        simultaneously.  Imagine an  inventory  file,  a purchases file,
        and a sales  file.   You  take  your  purchases,  increase  your
        inventory based on purchases, record sales, and then reduce your
        inventory  based  on  sales.   That's  three  integrated  files.
        Purchases  and  sales  are  used  to  update inventory.   Here's
        another  example.   If  you  recorded  your  customer names  and
        addresses every time you made  a  sale, then numerous entries in
        the sales file would have redundant information!  Why  not  just
        use a customer NUMBER, and  have  a separate customer file where
        you stored the customer number, along with  the  customer  names
        and addresses?  In this way, you could update  for  a  change of
        address merely  by  updating  the customer file, and not have to
        search your entire sales file, changing the address on each sale
        to that customer.  Preparing invoices is as simple  as  relating
        the customer file to the sales file, extracting name and address
        info from the customer file, and sales to each customer from the



        dBMAN by Versasoft           - 1 -             An Initial Review









        sales file.  The  linking  element  between  the  files  is  the
        customer number.  This is the  stuff  of  relational  databases,
        where you normalize your data  to  eliminate  redundancies,  and
        relate files easily for total freedom in data manipulation.

          The second distinction  that  any relational database has over
        file   managers  is  its  PROGRAMMABILITY.   The  more   complex
        applications  you  may  wish  to  design  would  require  typing
        numerous  commands  at  the  keyboard  to  accomplish  even  the
        simplest tasks.  These same commands can be programmed, saved in
        a COMMAND file, to automate such tasks.  Think  of such programs
        as  super  macros,  where  the  computer  executes  your  stored
        commands in sequences you design, to facilitate the  running  of
        your system.  Many people make a living out of designing turnkey
        database systems for business (offices, banks, stores, etc).  In
        fact, these database languages are so refined that they actually
        belong in  a  legitimate  class  of  their  own  as  programming
        languages!  With the utilities around these days, you could  use
        any text editor to write a dBASE system, compile it, and have it
        run as a separate stand-alone package, without ever even  having
        owned the actual database itself!  There are no dBMAN  compilers
        per se, but you do use an outside  editor  to  compose programs,
        and can run your programs with  the  runtime  package  available
        separately from Versasoft.  In other words, you can supply dBMAN
        custom programs to be  run  under  the  runtime  package.   Your
        customers do not have to own dBMAN!

          The IBM version of dBMAN sells for $295.  The ST version lists
        for $149.95.  It  is  identical  to  the IBM version.  This is a
        very  fair  price in  my  opinion.   I  would  not  hesitate  to
        recommend dBMAN to anyone wanting an incredibly useful tool  for
        data management.

          The product itself is delivered  on  two  single-sided  disks,
        unprotected.   One  disk is the dBMAN  interpreter  itself  with
        related files.  The other is a snappy little tutorial disk, that
        gets you going with the rudiments of using  dBMAN.  The tutorial
        disk also includes some sample dBMAN command files  for  mailing
        list management.  I ignored them in favor  of writing my own for
        the sake of flexibility, and as an  exercise, but they will give
        you the flavor of programming.  By  all  means,  print  out  the
        command files on this tutorial disk.  Read through them.   Study
        the  processes  and  logic  involved.   This  is a great way  to
        learn!

          The dBMAN package is an attractive grey slipcase, inside which
        is the hardcover  3-ring  binder holding the documentation.  Ah,
        the documentation.   It's  not  the best.  I found it sketchy on
        details regarding command  syntax.   This  product is definitely
        not dBASE compatible, I assure you, though everywhere  you  read
        that it is.  You can use a dBMAN command to CONVERT a dBASE data
        file to dBMAN format, but the programming languages are SIMILAR,
        not compatible.  For example, in dBASE, the command  to delete a



        dBMAN by Versasoft           - 2 -             An Initial Review









        file is "ERASE".  In dBMAN, the "ERASE"  command  merely  clears
        the  screen!   There  are  numerous  other  differences  in  the
        language, but they are similar enough so that  you would benefit
        from buying a dBASE III programming  book  at  a  bookstore  and
        studying  it  a little to get the hang of things.  If you are  a
        novice, you will not be able  to  dive  into  dBMAN  programming
        without a substantial investment  in man-hours spent deciphering
        the documentation.  Although the manual is accurate, it  is  not
        as  complete  as  it  could be,  and  does  not  have  the  best
        organization.  I remember looking hard to find the operator that
        would allow me to chain a  command line over more than one line.
        It was buried in a section of the manual titled "File Types"!!!

          There is no "LABEL" command.  This means that you will have to
        write your own label maker programs.  Label programs  are  among
        the simplest to write, so this is no big loss in my view.

          There is no text editor  built  into the product.  Please note
        that using  the  product  from command level does not require an
        editor.  You simply enter commands one after  the  other.   It's
        the programming that requires an outside editor.  This can  mean
        constant loading of your editor, then dBMAN, exiting, re-loading
        your editor, composing code, re-loading dBMAN,  etc.   I  use  a
        simple technique to simplify things.  On my 1-meg 520ST I create
        a 550K ramdisk with Solapak, copy the editor files and DBMAN.TTP
        to the ramdisk with Solapak's COPY2RAM program, and  work out of
        the  ramdisk.   My  data  and program files  are  on  a  floppy.
        Switching between  dBMAN  and an editor is a breeze when done at
        the speed of a ramdisk.

          Be careful in your choice of an editor.  It must be capable of
        producing pure ASCII files.  I used Final Word exclusively until
        I started using "procedures" in my programs.   There  was  never
        any prior indication of trouble, but using the  SET PROCEDURE TO
        command in any command files created with the  Final Word caused
        dBMAN to crash to the  desktop.   This problem gave me countless
        hours of grief until, on a lark, I loaded my procedure file into
        Regent Word.  Lo and behold, the last  byte in the file appeared
        on  my  screen  as  a  non-ASCII  character.  When I had  called
        Versasoft for  help,  one of the questions they had asked me was
        if I was certain the file contained only ASCII characters.  When
        you  save  a  Final  Word  file,  it  puts  an odd character  (a
        non-ASCII character) at its end as an end-of-file marker.   This
        is all it took to bomb my dBMAN programs.  It was a hard problem
        to  troubleshoot,  as  that  darn non-ASCII character  does  not
        appear  on  your screen in the Final Word.  I  now  use  another
        editor for dBMAN programming.

          Remember one command above all  others:  SET TALK OFF.  If you
        run  a  program and don't include that statement, each  line  of
        your code will be reflected onscreen  in  the  command  line  (a
        reserved area at the top  of the screen).  This can be a help in
        the debugging stages, but slows  down  execution  to  a  snail's



        dBMAN by Versasoft           - 3 -             An Initial Review









        pace.  My club membership list program runs in seconds with talk
        off, but with talk on it can take 15 minutes!

          The  "@SAY--GET"  commands  don't  permit  a  "RANGE"  clause,
        leaving it up to you to hack data input validation.  This can be
        done with a sprinkling of IF commands, CASE structures, or other
        techniques.  It can also be done with a  GETFILE structure.  The
        GETFILE is called at the level of the program that called it, so
        local variables are available to the GETFILE.  You can do almost
        anything you want in a GETFILE,  but the primary use would be to
        contain the code to validate the input a user may be typing when
        using  your  application.   There  are  provisions  for  PICTURE
        clauses.

          There  are  also  some  nifty  commands  for formatting  menus
        (VMENU, HMENU, BOX,  etc.)   but  I  have  not  tested them yet.
        dBMAN does not use GEM at all, so forget about using a mouse for
        anything.

          Support?  The manual states that Versasoft will try to respond
        to any written inquiries but must charge for  telephone  support
        at  the  rate  of  $25  for  6 calls of up to  5  minutes  each.
        Sheesh.

          I hope this narrative is helpful to  would-be  purchasers.   I
        highly recommend the product.  It works, appears to  work  well,
        and is  virtually  alone  in the ST software world.  Nothing but
        H&D Base comes close to  its  versatility and power, but whether
        Mirage will survive to support H&D Base is  anybody's guess.  Do
        yourself a  favor.   Buy almost any book on dBASE III before you
        novices get into dBMAN programming.  You won't regret the  extra
        expense!

          If you have questions or need some help, leave public messages
        to SYSOP (that's me!)  on the H.A.S.T.E.  BBS.  Myself or one of
        the other dBMAN fanatics will respond.  I  would like to see the
        club develop a series of  articles  to  supplement  the  program
        documentation.  Sophisticated products like these, being sold to
        as new  a  market as most of us ST'ers represent, almost require
        such user  support.   Contact  me  anytime  at  the  HASTE  BBS,
        713-955-9532, 24 hours, 300/1200/2400 baud.















        dBMAN by Versasoft           - 4 -             An Initial Review