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AM_KEY_T.HLP
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1991-04-27
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APPLICATIONS MAKER - HELP ON KEYS
When you opt to initialize a STRING ITEM as type KEY you are telling
the program that this item will be the basis of a LOOKUP into a
datafile. The purpose of a LOOKUP is to find and load a particular
record so that information it contains can be made available for use
in your application.
These KEYS are available to find records in any of the datafiles you
have chosen for your application. The target datafile is selected
from a window during the initialization of the KEY ITEM.
KEY SOURCES:
Your keys can be of five types: KEYBOARD entries, MENU files, AUTO-
FILL, BROWSE and EXPANDED. From these you will be able to find
records in many different ways, suitable to almost any need.
KEYBOARD KEYS: With the KEYBOARD KEYS your user enters the data that
will be the basis of the LOOKUP. Within this classification there
are two ways to find records: by their RECORD NUMBERS and by their
FILE INDEXES.
RECORD NUMBER lookups allow your user to enter the user-assigned
record number of a record.
With the FILE INDEX KEYS your user will enter the data contained in
the target record. The field containing the data for which you will
search must be declared as INDEXED UNIQUE. You will select your
field from a window filled with the INDEXED fields.
DATAMAGE offers three types of indexing: UNIQUE, CROSS and NON-
UNIQUE. Of these, only UNIQUE and CROSS indexed fields are suitable
for the absolute identification of a record, as the system will
reject new/edited records having duplications in these fields.
APPLICATIONS MAKER does not allow you to place CROSS-INDEXED fields
on the input screen. These fields might have a formula attached to
them or might be written into another file. When the lookup into the
file is executed, on entry of the last field in the cross-index, it
might fail. This would produce an intractable situation. If you
wish to allow your user to search the cross index you must use the
EXPANDED KEY type, detailed below.
MENU KEYS: With the MENU KEYS you will make a menu file with a word
processor, in pure ASCII mode. The menu file will be named at the
time you initialize your MENU KEY item. This file can have up to one
hundred choices in it. It must have TWO lines for each choice - the
first holding the text proffered to the user, the second containing
the data returned to the program. See the docs for APPLICATION MAKER
for further details on MENU items.
The MENU KEYS are used to find a particular record, associating it
with a descriptive text which is chosen by your user. You might have
an application that processes sales and returns. You might wish to
add the total generated to one record in a file if the transaction
was sale, and another if it was a return.
As with the KEYBOARD KEYS your menu file may return ether a RECORD
NUMBER or the contents of a field indexed as UNIQUE. Since there is
only one item returned from the menu file the MENU KEYS may not be
used in conjunction with the CROSS INDEXES.
AUTO-FILL KEYS: With the AUTO-FILL KEYS you can read/write data
to/from a particular record. You make the KEY data a part of your
application, and the same record is found every time. Using the
scenario above, you might branch to a different part of your
application to process the sales and returns. Then the choice of the
record in which to place your total could be made for the user.
AUTO-FILL keys may use ether RECORD NUMBERS or UNIQUE INDEXES.
BROWSE KEYS: With the BROWSE KEYS the target datafile is read and
displayed in a window opened on top of your screen. You select the
field inertly displayed, usually the description of the record. The
user may opt to change the display field.
Your user can scroll through the file with his up/down arrow keys,
page up/down keys or home/end keys. When the desired record is
highlighted your user hits return to select it.
You also specify the field in the target file that will be returned
to the program, and fill the item. Your user may NOT change the
field that is returned.
EXPANDED KEYS: With the EXPANDED KEYS your application screen will
clear, the speaker will beep, and the lookup will be displayed
complete with file number and it's description. Your user will have
the option of searching on the RECORD NUMBERS or the FILE INDEXES.
If your user opts for the file indexes the program will display a
screen similar to the FIND RECORD function in the BASE program. It
will prompt your user for all of the indexed fields in the target
datafile, which may be filled with a search value or bypassed by
pressing return.
If your user fills a field that is declared as indexed UNIQUE, or
fills all of the fields declared as CROSS-INDEXED and a match is
found in the targeted datafile the record will read in and the
program will continue.
If your user fills a field or fields declared as indexed NON-UNIQUE,
or some but not all of the fields declared as CROSS-INDEXED and a
match is found the record will be displayed on a screen similar to
the record access screen in the BASE program. Your user will then
view the record. After pressing Q to quit the record your user will
have the option of accepting the record displayed, or continuing the
search for the desired record.
If a record is not found the program will offer your user the option
to retry the search, or to quit. If your user opts to quit the
search the program will offer to find the record on any of the modes
above. If your EXPANDED KEY item has a label to handle bypasses your
user will have the option to continue, if not the continue option
will be replaced by the option to abort. If the abort option is
selected the APPLICATION will end with an error.
KEYS NOT FOUND:
Any of the KEY TYPES may fail. Your user may enter data into a key
item that is not found in the target file. Or your user may BYPASS
the key item by simply pressing return on it.
The KEY ITEMS have the built-in option to handle bypasses by either
branching to a label, or aborting the application. This is defined
during the initialization of the KEY item.
In the event of your user entering data that is not found the program
will not halt, but will display five options to deal with the
situation: RETRY, CONTINUE/ABORT, EXPAND, BROWSE and ENTER RECORD.
If your KEY ITEM has a label to go to on the bypass of that item the
second option offered to your user will be CONTINUE, else the second
option will be ABORT.
RETRY will allow your user to try the KEY entry again.
ABORT will end the application and CONTINUE will bypass the item.
EXPAND Will allow your user the option to search the file on RECORD
NUMBERS, or the FILE INDEXES. If the FILE INDEX option is selected
ALL of the indexes will be available as search targets.
BROWSE will produce and fill the BROWSE WINDOW, and allow your user
to video-select his record from the file.
ENTER RECORD will allow your user to enter a new record into the
target file. This record will then become the source of the data
read/written to/from that file.
WRAP-UP:
As you can see, APPLICATIONS MAKER provides many ways to do a LOOKUP.
There is NO other data program that offers this power and flexibility
while finding records in relational files.