Task 3 - Specifying Screen Field Details [ HP ALLBASE/4GL Developer Self-Paced Training Guide ] MPE/iX 5.0 Documentation
HP ALLBASE/4GL Developer Self-Paced Training Guide
Task 3 - Specifying Screen Field Details
After you have created the image of a data screen with the screen
painter, you usually need to specify some further details for the data
fields on the screen.
These details include automatic data movement, field-associated
functions, and some special field processing indicators. For two fields
on your data screen, some default values will already be created based on
the field specification you used to define the field. In most of
these cases you will only need to add the automatic data movement
specifications.
Menu Path
To access the screen field details screen from the main
menu:
1. Select the Screens option.
2. Choose Details.
Screen Description
This screen allows you to complete the definition of each input or
display field on an application data screen.
Click here to view figure.
Screen Field Details Screen
First you must enter the name of the screen, and then step through the
fields on the application data screen completing their respective
details.
The complete screen field details screen is used for each field on your
application screen.
To enter the field values:
Field Entry Explanation
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Screen product_scrn The name of the data screen that you are
defining field details for.
Table 3-0. (cont.)
Field Entry Explanation
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Sequence Number Accept the default. The field number, defined by the sequence
of data fields on your data screen.
The field sequence for this screen is set
automatically from top left to bottom
right. This sequence of fields and
allocation of field numbers is determined
by the Automatic Numbering flag on the
screen header screen.
When you press the Return key, the details
already recorded for this field are
displayed at the bottom of the screen. The
dictionary specification details have been
automatically transferred to this screen,
and many of the fields contain a default
value.
Field Spec. Name Accept the default. This field defaults to the dictionary field
specification name used to define the
attributes of this screen field in the
screen painter.
Blanking out this field changes the last
nine fields on the field details screen to
input fields. These fields cannot be
changed when a link to the dictionary
exists through a field specification name.
If you have blanked out the field
specification name, re-enter the name
product_no to protect the screen field
specification again.
Primary F-product_no.product This entry specifies that when the cursor
is moved to this screen field, the current
contents of the field product_no from the
file buffer product are moved to the screen
buffer and then displayed.
On completion of data entry, the new
contents of the screen field are moved to
the file buffer. (Refer to "Entry Notes"
section in this lesson.)
To enter behavioral characteristics fields:
The next six fields define the way the field behaves on the screen.
This is not dependent upon any data type, format, or validation
specifications.
Field Entry Explanation
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Input/Display Accept the default. This indicates whether this data field is
an input field (I), or a display field (D).
It enables you to override the setting you
specified in the screen painter.
Required Field Accept the default. Indicates whether this field must be
non-blank for alphanumeric, or non-zero for
numeric fields, for the field value to be
accepted.
When the user attempts to move off a
required field that has been left blank,
the field is highlighted and the cursor
remains on it. The user can move back to a
field with a lower sequence number, or
enter data into the current field. The
user cannot commit the screen with the
Commit Data function key while a required
field remains blank.
Help Name Accept the default. This is the name of the help screen that is
called if the user presses the Help
function key while the cursor is on this
field.
If you have defined a help screen name for
this field specification in the dictionary,
that name is automatically transferred to
this field. If you haven't specified a
help screen name, HP ALLBASE/4GL creates a
default help screen name with the same name
as the field. You can change the help
screen name here without affecting the
dictionary specification.
Table 3-0. (cont.)
Field Entry Explanation
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Clear on COMMIT Accept the default. This field works in conjunction with the
Clear Fields on COMMIT setting specified on
the screen header for this screen. The
relationship is an OR relationship. That
is, if the setting for either is Y, the
field is cleared. Only if both are set to
N will the field not be cleared.
Include in SHOW Accept the default. This specifies whether the field should be
manipulated when it is referred to from a
logic block SHOW command. With some
fields, you may want to ensure that the
only time anything is ever done to them is
when an explicit reference is made to them.
The SHOW command is used in HP ALLBASE/4GL
logic to redisplay data in a screen field.
You will learn about the SHOW command in a
later lesson.
Automatic Flow to Accept the default. So far, all the fields that you have used
Next require you to press the Return key to
signal that the field entry is complete.
In the same way, the fields you define for
an application screen normally require the
user to press the Return key to complete a
field entry. Under some operating systems,
setting the Auto Flow to Next field to Y
causes HP ALLBASE/4GL to generate an
implicit Return when the user fills the
field. Although displayed on this screen,
that facility is not available under the
MPE/iX operating system.
To enter function specification fields:
You can associate a logic function with each screen field. The next four
fields specify how the function for this field is executed. This
function enables you to perform some data manipulation or validation when
data is displayed in the field, or entered into the field.
The field function you are naming here will read the product file for a
record with a key value matching the value entered by the user.
Field Entry Explanation
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Function product_key_read This is the name of the function to be
associated with this field. If you leave
this field blank, entry into the next three
fields is not possible.
Prior/After/Both A This entry specifies when the function is
executed.
There are three available options. P
indicates that the function is executed
prior to data entry, when the user moves
the cursor onto the field. A indicates
that the function is executed after the
completion of data entry for the field;
this is only valid for input fields. B
indicates that the function is executed
both prior to and after data entry.
Table 3-0. (cont.)
Field Entry Explanation
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Perform Function on Accept the default. This field relates to the behavior of the
SHOW field under a SHOW command from a logic
block.
At times the function may perform some data
formatting or extraction that is essential
for the correct data to be displayed. In
this case, the function needs to be
executed when the field is displayed under
control of a SHOW command.
After Function if Accept the default. This field only applies to non-required
Blank screen fields. It indicates whether the
function is executed even if the screen
field has been left blank.
You may have noticed that only one function
can be called from the field, yet the
function can be called at three distinctly
different times; prior, after, or on SHOW.
HP ALLBASE/4GL has two switches (*ENTERED
and *SHOWING) that you can test in the
function to determine when the function is
being executed. This allows you to use the
one function to perform three different
operations, depending on the processing
stage at which the function is executed.
To enter validation and format specification fields:
The bottom nine fields on the screen are a copy of the same fields from
the dictionary field specification screen.
If you have entered a field specification name in the Field Spec. Name
field at the top of this screen, you cannot change any of this group of
fields. You can only enter local field definitions if there is no field
specification name associated with the application screen field.
The fields are not described here as they have exactly the same meaning
as their counterparts in the field specification screen.
To complete the Product Number screen:
1. Once you have completed all of the details for this particular
screen field, press the Commit Data function key.
When you press this key, the cursor returns to the Sequence Number
field.
The details for the next field on the application screen are then
displayed, enabling you to enter the remaining details.
As you go through the screen fields, HP ALLBASE/4GL creates a primary
data movement identifier automatically. This data movement identifier
consists of the field specification name for the current field and the
file record specified for the first field on the screen.
To complete the remaining screen field details:
Now you are ready to complete the screen field details for the rest of
the training screen.
* Enter the details listed. Only those fields that require an entry
other than the default are listed here.
* After entering the details for each field, press the Commit Data
function key.
* If you make an error in a particular field of the screen, you can
display its details by entering its sequence number and pressing
the Return key.
The field details are then displayed so you can modify them, and
commit them again.
The following entries are required to complete the screen field details.
Description
Sequence Number 2
Primary F-description.product
Supplier Number
Sequence Number 3
Field Spec. Name supplier_no
Primary F-supplier_no.product
When you defined the supplier number field in the screen painter, you
didn't use the dictionary field specification name method. For this
reason, a default name is not displayed with the rest of the field
details. When you enter the name supplier_no, the fields at the base of
the screen become display fields.
Lead Time
Sequence Number 4
Field Spec. Name lead_time
Primary F-lead_time.product
Required Field N
As with the previous field, you didn't use the dictionary field
specification name method to define this field in the screen painter;
therefore, no default name was displayed.
You have now completed the definition of the fields for this screen. As
with a record layout, you must generate the screen before it can be used.
The "Entry Notes" section that follows provides additional information
for some of the fields. If you wish, skip this section and continue on
to "Task 4 - Generating the Data Screen."
Entry Notes
Data Movement
The Primary, Default and Other fields define the automatic data movement
that occurs as the user moves through the fields on the application
screen. The three types of data movement are:
Primary When HP ALLBASE/4GL displays a screen field, it moves
the contents of the primary data movement field to
the screen and displays the field contents. For an
input field, HP ALLBASE/4GL moves the contents of the
screen field to the primary data movement field after
the user completes data entry for the screen field.
Default If the screen field is blank, HP ALLBASE/4GL moves
the contents of the default field to the screen and
then displays its contents. If the screen field is
not blank, no action takes place.
Other For input fields, HP ALLBASE/4GL moves the contents
of the screen field to the other data movement fields
when the user completes data entry for the field.
Each input field can have up to three other data
movement fields.
NOTE You cannot specify both a primary and a default data movement
field. They are mutually exclusive. A field can only have one
source for its data, however, you can combine either of these
"source" movement fields with up to three Other data movement
specifiers.
The fields you name in these automatic movement specifiers can be any of
the following:
* A file record field reference.
* A screen field reference.
* A scratch-pad field reference.
* A variable.
* A numeric or alphanumeric constant (default data movement field
only).
NOTE The file record field specifier consists of three components. The
prefix F- indicates that this is a file buffer field reference.
Next, the field name product_no indicates the field to be used, and
the file name product specifies the file buffer to be used. These
last two terms are separated by a single period (. ). Refer to
the HP ALLBASE/4GL Developer Reference Manual for further
information on naming and referencing rules.
As the Primary and Default move specifiers are mutually exclusive (you
can only move data into the screen field from one of these sources), HP
ALLBASE/4GL skips over the Default move field. If you wanted to alter
this field, you would need to delete the Primary move specifier, and then
specify the Default move field. No Other move fields are to be entered
in this example. When you leave the first Other move field blank, HP
ALLBASE/4GL skips over the next two.
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