Night Owl 6/Night Owl's Shareware - PDSI-006 - Night Owl Corp (1990).iso/025a/isamto.zip/ISAMTOOT.DOC

Text File | 1991-11-05 | 11KB | 267 lines

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│           ISAMTOOT         -       WORKBOOK NOTES             │
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GENERAL

You need to have Microsoft's BASIC Professional Development System
7.0 or higher.  If when you installed PDS you didn't elect to
install the ISAM "option" then you should re-run your installation
to include it.

To avoid confusion we have deliberately avoided including any of
the excellent libraries MS furnishes with PDS.  They ARE useful and
important tools -- particularly in the later lessons -- but our
judgement was that we wanted to focus on ISAM rather than expanding
the study to the libraries as well.

We have also included some "bad" programming practices in the
interests of simplicity and clarity.  (i.e., getting data with the
LINE INPUT function.)  We've noted these "flaws" as we create them
and you should flag them for further study and resolution -- again,
our focus is ISAM, not programming in general.

ISAMTOOT was developed in PDS 7.1 on a system that accepted MS's
"default" installation directories and sub directory structure(s).

When we call for a "DOS prompt" entry of -- say -- \bc7\bin\qbx, we
are intending to start the PDS environment AND to be in the
directory with QBX.EXE, etc.

Technical support for this instructional course is available on
CompuServe @ 70146,51, FAX: [phone], or 817-488-4940.  The
telephones are answered 24 hours a day, 7 days a week.


LESSON #1

     OBJECTIVE:  Create, dimension, open and add data to a bare
     bones ISAM database.

     MS FILES NEEDED:  QBX.EXE, PROISAMD.EXE (Please note that we
     are using the larger of the two TSR's MS furnishes -
     PROISAMD.EXE, rather than PROISAM.EXE

               Comment:  The smaller of the TSR's does save
               some memory, but you can't create indexes with
               it and more importantly, the various utilities
               MS furnishes to repair and pack database files
               need to have PROISAMD.EXE rather than
               PROISAM.EXE.  Certainly any commercial
               application should use the "full featured"
               version.

     TO START:  At the DOS prompt, type: PROISAMD and then press
     your ENTER key.  Your system will display the message:
     "PROISAM successfully installed."

               (If you are continuing an adjourned lesson,
               then the message might be:  "PROISAM already
               installed."  To remove PROISAMD from memory
               you should type (at the DOS prompt): PROISAMD
               /D and press the ENTER key.)

     Now type:  QBX and press the ENTER key.  The screen should
     clear and you find yourself in the programming
     editor/environment.


Step #1.  Type DEFINT A-Z and touch ENTER.

Step #2.  Touch an apostrophe    '    (to make this next line a
          comment) and do a line of dashes.  (    -    )

Step #3.  Touch an apostrophe:    '    and type:    ISAMTOOT.L1

               You are correct in thinking that this file you are
               creating -- the source code for lesson 1 -- would,
               in the normal course of events have the extension:
               .BAS.  We have opted for this extension to maintain
               uniformity within the course and avoid possible
               damage of your other source code files.

Step #4.  Another apostrophe and another line of dashes.

Step #5.  Touch ENTER again to insert a blank line and then type:
          CLS.  (The first executable line of your program,
          clearing the screen.)

Step #6.  Another blank line, then type:  TYPE lesson1data

               We are beginning the actual defining of our first,
               bare bones, database.  Don't be stingy with blank
               lines, spaces, indenting, comments.  They cost you
               nothing in a compiled program and the small
               overhead they create within the environment is more
               than paid back in clarity and ease of reading.

Step #7.  Define three fields -- all strings, all 35 characters
          long.  The first is for the name, the second for the
          address and the third for the city state and zip.

Step #8.  Type END TYPE

          Your finished definition block should look like:

               TYPE
                    name AS STRING * 35
                    address AS STRING * 35
                    cityStateZip AS STRING * 35
               END TYPE

          (Perfectly all right to peek at the ISAMTOOT.L1 source
          code.  As a matter of fact, even though it is
          considerably larger than the one you are writing, it will
          run if you load it into QBX and do Shift+F5.)

Step #9.  Now we dimension  a variable for the lesson 1 data.
          Type:

               DIM lesson1record AS lesson1data

Step #10. Now we actually open the database and table . . .

          OPEN "lesson1.MDB" FOR ISAM lesson1data "lesson1table"_
          AS  #1

          (Please note that this is entered in a single line of
          code.  The underscore:  _   is used to indicate that the
          two lines are actually one.)

Step #11. We skip creation of an index for this first lesson, we'll
          let ISAM use the one it creates when it adds records --
          the null index.  It is automatically selected when none
          other is specified.

          The database is now ready to receive some data, so we'll
          set up a loop to gather information from the operator.

Step #12. Type in the following structure:

          DO

               CLS
               PRINT , , "There are "; LOF(1); " records in _
                          the file."
               PRINT
               PRINT , : LINE INPUT "First & Last Name: ";_
                                    lesson1record.name
               PRINT , : LINE INPUT "          Address: ";_
                                    lesson1record.address
               PRINT , : LINE INPUT "City, State & Zip: ";_
                                    lesson1record.cityStateZip
               PRINT
               PRINT , "<S>ave    -    <E>dit      -       <Q>uit"
               PRINT , "     Touch  S   or    E    or     Q"

               dataDecision$ = UCASE$(INPUT$(1))

               IF dataDecision$ = "S" THEN
                    INSERT #1, lesson1record
                    LOCATE 25, 40: PRINT " Saved ";
                    SLEEP 1
                    EXIT DO
                    END IF

          LOOP UNTIL dataDecision$ = "Q"

Step #13. That structure is about as rudimentary as you can get.
          LINE INPUT is not a good way to get data into a program
          because the operator can enter anything, up to 32,000+
          bytes, and doesn't return control to the program until
          they press ENTER.  It serves our purposes here, but
          invites trouble in anything other than an "author-
          operated" situation.

          It's no fun to enter data unless you can see the "fruits
          of your labor," so, to wrap up lesson one, lets take a
          look at what we've entered in the database.

Step #14. Let's clear the screen and then write another loop to
          look at our data . . .

          CLS
          PRINT
          PRINT , "Total records now in the file: "; LOF(1)
          PRINT
          PRINT , "Now, we report the contents of the file . . . "
          PRINT

          MOVEFIRST #1

          DO UNTIL EOF(1)
               RETRIEVE #1, lesson1record
               PRINT , lesson1record.name
               PRINT , lesson1record.address
               PRINT , lesson1record.cityStateZip
               PRINT , "------------------------------------------"
               SLEEP 1
               MOVENEXT #1
          LOOP

Step #15. This will display all the records in the database and
          then the program will end.  With Shift+F5, you can re-
          start the program (it will show the number of records in
          the file), enter another record, save it and then it will
          fall through this "reporting loop" to show you everything
          you've entered.  Again stopping after reporting all the
          records.

          Polishing things up a bit would mean you would type in
          the following . . .



          PRINT
          PRINT , "We've reached the end of the file."
          PRINT
          PRINT , "Press Shift+F5 to restart, enter a"
          PRINT , "record and report file contents."
          PRINT
          PRINT
          END


SUMMARIZING THE LESSON:  You created and added records to an ISAM
                         database.  While rudimentary, the program
                         you wrote will, in fact, manage data for
                         you.

                         If you substitute LPRINT statements for
                         the PRINT statements in the "reporting
                         loop" you can get hard copy of your data.


LOOKING AHEAD            To be really useful, your database needs
                         to become more intricate.  As it stands
                         now you wouldn't be able to sort to last
                         name or city or even zip code (as the
                         post office requires for bulk mailings.)

                         In Lesson #2, we will correct those
                         shortcomings AND we will be adding
                         INDEXES so that you can order your data
                         in more useful ways.

                         This lesson will seem very much like "See
                         Spot run." by the time you are managing
                         tables of 15-20 fields each and then
                         relating (as in relational database) the
                         data in distinctively different tables.

                         Just keep your dial set right here!



EDITOR'S NOTE:  The file:  ISAMTOOT.ENR has complete pricing
information for the full ten (10) lesson tutorial on ISAM.  The
course is offered with an unusual money back guarantee of
satisfaction:  If you are not delighted with the Course, just
return the materials for a prompt, no hassle refund.


Entire Contents Copyright 1991, Kirk Woodward d/b/a People Centered
Programs, PO Box 610171, Dallas, TX 75261-0171.  CompuServe
70146,51 . Enrollments ONLY: 1-800-553-5883 . FAX: [phone]
Voice: 817-488-4940
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