Dec 132017
 
Ashton Tate DBASE IV Tech notes for Oct 90.
File TN9010.ZIP from The Programmer’s Corner in
Category Dbase Source Code
Ashton Tate DBASE IV Tech notes for Oct 90.
File Name File Size Zip Size Zip Type
DIALOGUE.TXT 18594 7086 deflated
ETC.TXT 10803 4478 deflated
GETPOINT.TXT 12967 3623 deflated
MEMPRIM.TXT 13200 5170 deflated
OVRD-MCH.TXT 3997 1751 deflated
RDEEMQBE.TXT 7474 3170 deflated
SETFAR.TXT 14111 4659 deflated
WPWEXP.TXT 8738 2810 deflated

Download File TN9010.ZIP Here

Contents of the DIALOGUE.TXT file


Dialogue
Questions and Answers

A Window By Any Other Name.

Q: I am using an ON KEY LABEL in my program which I have active
while using a screen form to edit records. My screen form contains a
memo window. Pressing the ON KEY jumps to another work area, opens
another database, and enters BROWSE mode. Upon quitting the BROWSE, I
return to the original work area. The memo window is now a memo
marker and an error message displays the message Window Not Defined.
What has happened?

A: The Form.gen file, which is responsible for compiling your
screen form, defines windows (for the memo window) to a default memory
variable named window1. Merely activating another format file in
another work area with a memo window caused the second format file to
also DEFINE WINDOW WINDOW1. The second format file also does a
DEACTIVATE WINDOW and RELEASE WINDOW WINDOW1 which eliminates the
window defined by the first format file.

It would be necessary in this case for you to modify the .fmt file of
either of the two windows and change the name of one of the windows so
they are not in conflict.

The Bottom Line

Q: Why is it that Ctrl-Y does not work when I attempt to delete
the last line in a band during my report design?

A: Ctrl-Y was modified in version 1.1 for use in the MODIFY
COMMAND editor where there existed a problem with the ability to
physically delete the last line. Correcting the problem there altered
the functionality when editing bands in reports. The workaround is to
move the second-to-last line down using F6 Select and then deleting
the now-blank second-to-last line.

Windows With (Status) Bars

Q: After creating a screen form, I received the message Illegal
Value when I attempted to display the data. From the way the
information displayed, it appears as if a memo window which I have
toward the bottom of my screen is causing it. How do I prevent the
error?

A: You will need to move the window up where it will not overlap
the status bar.

While in the design screen, you might not realize that the memo window
will overlap the status bar because dBASE IV displays the status bar
two lines above the position it will ultimately appear at in the final
screen form. This is because the status bar always appears on line 22
and the virtual screen of the form designer is positioned two lines
lower than the actual screen (to allow for the Menu and Ruler).

If you place a memo as a marker on row 20 or 21, and then proceed to
size the window from that upper-left position (row 20/21) to a
lower-right position and the status bar is on, you will get the error
message you saw when you try to display data using the screen form.
The window size will be truncated to accommodate the status bar.
However, the resulting window size will be too small and will cause
the error message.

Summary Commands Don't Echo Anymore

Q: I've made the switch from dBASE III PLUS to dBASE IV and
everything has been pretty smooth with one exception. I have programs
that produce reports that were summarized with record counts that are
no longer being printed. It seems to me like the commands are either
being ignored or some functionality has changed. Could you shed some
light on this?

A: Actually, this is an issue that first presented itself when
dBASE IV was originally introduced. In dBASE III PLUS, SET PRINT ON
gave printed results to commands like COUNT and SUM. In dBASE IV, it
is necessary to direct the result of a COUNT, SUM or AVERAGE statement
to a memory variable. Then use a syntax such as

? AT

to print the result on the page. Although this would appear to be a
removal of functionality, all the summarizing features noted here are
now directly implementable in a dBASE IV report. The only reason
COUNT and SUM statements appearing after REPORT FORM commands were
implemented in this way is because there was no way to include them in
the more limited dBASE III PLUS report generator.

High Resolution Error

Q: While attempting to run a program I made with the Application
Generator, the program was halted by an error referencing a variable
called gn_error and the message said the variable was not found. I
did not create this variable. What causes this error?

A: There is a problem with Menu.gen when generating code for
EGA43 video mode. The .prg file references the variable gn_error
before it initializes it. This results in an error when you try to run
the program that says Variable not found gn_error. The workaround is
to avoid using 43 line mode when generating or, if 43 lines are
required, modify the .prg file generated by the Applications Generator
and comment out two IF structures near the beginning of the code. The
first begins with

IF gc_display <> "EGA43"

and the other is right after it and starts with

IF gn_error <> 0

These two structures just make sure that the display mode was actually
set to 43 line mode and give an error message if it couldn't set it.
Commenting them out just removes this safety feature.

QBE Takes Over the Show

Q: I am developing an application where I want to give the users
access to the QBE interface but do not wish for them to be able to
change or update any records while in QBE. I tried to USE the data
file with the NOUPDATE qualification and then enter QBE to create the
query. When I press F2 to view the selected data, I am still able to
edit it. Since I can't trap the F2 key here, the situation looks
bleak. Have you any suggestions?

A: The .qbe file is overwriting your preferences for NOUPDATE by
opening any specified files again. Try copying the code from the .qbe
into a .prg file and executing the view as a program. If the view is
not complex (that is it does not CREATE, SORT, or INDEX but can USE,
SET INDEX, SET FILTER and SET FIELDS), you can set this up as a .vue
file that is still called from your program using SET VIEW TO.

Print Menu Availability

Q: When I start to print a report from the Control Center, I
highlight the report name and press Enter. The Print menu will
appear. I then go to the Print: Destination menu to select the
printer I want to print with. It's not actually a pop-up menu but
more like a multiple choice list within a single window. If you run
the report from a .prg or the dot prompt, you don't get the Print
menu. Is there any way to activate it?

A: No, sorry. You can program a list of printer drivers into a
pick list using the Application Generator without a lot of trouble. A
pick list in a popup can be used with the PROMPT FILES LIKE *.pr2
option. You also might try saving different drivers into different
print form (.prf) files and name the .prf files so that they are
easily associated with the different printers you have.

If you're running from the dot prompt or a program and it is not
necessary to give the user a choice, simply issue the command

_pform = ".PRF"

or

_pdriver = ""

right before you run the report.

Record Runaround

Q: I'm using a name and address database and normally work from
the dot prompt. After making an append and pressing Ctrl-End to save
it, the record pointer always goes to the last record in the index. I
would like to be able to call a program to print some information from
this newly appended record, but the record pointer does not follow
it. dBASE III did not work this way; it followed the new addition.

A: Under the Records menu is the option Follow record to new
position. Change this to YES and the pointer should follow the record
in the index.

Macro File Swapping

Q: I have an application wherein I can call several macros from
an edit routine. So many, in fact, that I need to be able to change
macro files. Is there a way I can do this without leaving the edit
routine?

A: By using ON KEY LABEL, you can call a UDF that could allow you
to change macro files. The ON KEY LABEL statement would appear in the
setup portion of your program (or in a setup program that loads when
you first begin a dBASE IV session). The statement would appear as

ON KEY LABEL


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