HP 3000 Manuals HP 3000 Manuals
Task 2 - Defining the Function Details
Having created the function header, you can now define the function
details.
Menu Path
To access this screen from the main menu:
1. Select the Logic option.
2. Select the Functions option.
3. Choose Details.
Screen Description
This screen is identical in appearance and operation to the process
details screen. The only difference is that you are creating a function,
not a process. It uses the same step numbers, actions, and commands as
the process details screen and it behaves in a similar manner.
The function you will create differs according to the data manager you
are using.
Read on if the application you are developing is KSAM based.
Turn to HP ALLBASE/SQL Based Application if you are developing the HP
ALLBASE/SQL based application.
Turn to HP TurboIMAGE/iX Based Application if you are developing the HP
TurboIMAGE/iX based application.
Developing a KSAM Function
This is the function that you will create:
1 FILE *READ product *KEY=*
2 SHOW *REFRESH
When the user enters data into the product_no field on the screen and
presses Return,
* The FILE command searches the product data file for a record that
has a key that matches the data entered by the user.
* If a matching record is found, the SHOW command displays the data
contained in the file record on the screen.
* If no match is found, the SHOW command displays the entered data
again, and the user can continue to complete the screen.
The screen image shows you what the screen will look like when you have
entered the function.
Click here to view figure.
Completed Function Details Screen
To enter the field values:
Field Entry Explanation
---------------------------------------------------------------------------------------
Function Name product_key_read This will be the default value if you have
just created the header for this function.
Step Number Accept the default.
Action Accept the default.
Command FILE You will see the FILE window appear. The
window is exactly the same as the one you
used when you were defining the process.
File Operation *READ This time you want to read a record from
the file. You can enter this command as
READ without the asterisk.
Table 4-0. (cont.)
Field Entry Explanation
---------------------------------------------------------------------------------------
*NOLOCK Accept the default.
File ID[.Record] product This is a reference to the product file
using the default record layout.
*INDEX= Leave blank. This field allows you to specify which
index is used to access the file. Leaving
it blank means that the file is accessed
using the index specified by the current
value in the communication area field
*INDEXNO.
HP ALLBASE/4GL initializes the value in
*INDEXNO to 1 when an application starts,
assuming that all file access is to be via
the primary key.
*KEY= * Specifies the value to be moved to the key
field of the file buffer before the file
read is performed.
The * refers to the internal buffer of the
current screen field. As this function is
called from the product_no field, the *
refers to the contents of the product_no
field on the data screen.
If you don't specify a key, the file read
takes place using the current contents of
the key field in the file buffer.
To complete this command:
1. Press Commit Data .
When you press this key, HP ALLBASE/4GL clears the window and displays
the entered command at the first line of the function. You will see that
the *KEY= * clause is included in the command line.
To enter the next command:
Field Entry Explanation
---------------------------------------------------------------------------------------
Step Number Accept the default.
Action Accept the default.
Command SHOW This command redisplays the fields on the
screen.
To Complete the *REFRESH Notice that you can enter either lowercase
Command or uppercase characters for the word
REFRESH. The *REFRESH clause specifies that
data is moved from the data movement fields
to the internal screen buffers before the
fields are redisplayed.
All the fields on the screen have been
created with primary movement fields from
the product file. This means that the
current contents of the file buffer are
displayed by this command.
To complete this command:
1. Press Commit Data .
HP ALLBASE/4GL displays the new command line and clears the window. This
function is now complete.
To generate the function, refer to the "Generating A Function" section
following the instructions for SQL and TurboIMAGE/iX.
Developing an SQL Function
For an HP ALLBASE/SQL application, this is the function that you will
create:
1 SQL find_prod
2 FILE *NEXT product
3 SHOW *REFRESH 2 4
When the user enters data into the product_no field on the screen and
presses Return,
* the first step executes the SQL commands in the find_prod SQL
logic block. This SQL block contains a SELECT command to retrieve
the record matching the product number value entered by the user.
You will create this SQL logic block in the next lesson.
* The FILE *NEXT command following the SQL command is equivalent to
an SQL FETCH command. This command positions the cursor on the
first row of the active set, and retrieves the record into the
file buffer for the product table.
* The remaining commands in the logic block then use this data as
required. If the active set for the cursor is empty, the FILE
*NEXT command encounters an end-of-file condition.
This example demonstrates the standard technique for retrieving SQL data
from an application. To retrieve a record you must perform the following
steps:
1. Use a SELECT command in an SQL logic block to declare and open a
cursor.
2. Use a FILE *NEXT command in a logic block to position the cursor
on the first record, and retrieve the record into the file buffer.
Both these steps must be in the same process, although they do not need
to be in the same logic block. For example, you can use the SELECT
command in an SQL logic block called from one function, and the FILE
*NEXT command in another function, provided both functions are called
from the same process. You cannot use a SELECT command in one process,
and the FILE *NEXT command in another process because HP ALLBASE/4GL
automatically closes all open HP ALLBASE/SQL cursors at the end of a
process.
The screen image shows you what the screen will look like when you have
entered the function.
Click here to view figure.
Completed SQL Function Details Screen
To enter the field values:
Field Entry Explanation
---------------------------------------------------------------------------------------
Function Name product_key_read This will be the default value if you have
just created the header for this function.
Step Number Accept the default.
Action Accept the default
action.
Command SQL This displays an open window.
To Complete the find_prod The name of the SQL logic block that you
Command will define in the next lesson. The
find_prod SQL logic block will declare and
open a cursor in the product table.
To complete this command:
1. Press Commit Data .
When you press this key, HP ALLBASE/4GL clears the window and displays
the entered command at the first line of the function.
To enter the next command:
Field Entry Explanation
---------------------------------------------------------------------------------------
Step Number Accept the default of
2..
Action Accept the default of
A.
Command FILE Again you will see the FILE window appear.
The window is exactly the same as the one
you used when you were defining the
process.
File Operation *NEXT After placing the SQL cursor in the correct
position, you want to retrieve the first
record found by the SQL SELECT command.
You can enter this command as NEXT without
the asterisk.
*NOLOCK Accept the default.
File ID[.Record] product This is a reference to the product table.
To complete this command:
1. Press Commit Data .
When you press this key, HP ALLBASE/4GL clears the window and displays
the entered command at the second line of the function.
To enter the next command:
Field Entry Explanation
---------------------------------------------------------------------------------------
Step Number Accept the default.
Action Accept the default.
Command SHOW
Table 4-0. (cont.)
Field Entry Explanation
---------------------------------------------------------------------------------------
To Complete the *REFRESH 2 4 Notice that you can enter either lowercase
Command or uppercase characters for the word
REFRESH. This command redisplays the fields
on the screen.
The *REFRESH clause specifies that data is
moved from the data movement fields to the
internal screen buffers before the fields
are redisplayed. All the fields on the
screen have been created with primary
movement fields from the product file.
This means that the current contents of the
file buffer are displayed by this command.
The 2 4 portion of the SHOW command tells
HP ALLBASE/4GL only to refresh fields 2 to
4 of the screen.
To complete this command:
1. Press Commit Data .
HP ALLBASE/4GL displays the new command line and clears the window. This
function is now complete.
To generate the function, refer to "Task 3 - Generating the Function"
following the instructions for TurboIMAGE/iX.
Developing an HP TurboIMAGE/iX Function
This is the function that you will create:
1 DM IMAGE *LOCK :D-traindb :R-product
2 FILE *READ product *KEY=*
3 SHOW *REFRESH
When the user enters data into the product_no field on the screen and
presses Return,
* The DM IMAGE *LOCK command places a logical HP TurboIMAGE/iX lock
on the product data set.
* Then the FILE command searches the product data set for a record
that has a key that matches the data entered by the user.
* If a matching record is found, the SHOW command displays the data
contained in the file record on the screen.
If no match is found, the SHOW command displays the entered data
again, and the user can continue to complete the screen.
The screen image shows you what the screen will look like when you have
entered the function.
Click here to view figure.
Completed HP TurboIMAGE/iX Function Detail Screen
To enter the field values:
Field Entry Explanation
---------------------------------------------------------------------------------------
Function Name product_key_read This will be the default value if you have
just created the header for this function.
Step Number Accept the default.
Action Accept the default.
Command DM As with the DM commands that you defined in
the product_proc process, an open window is
displayed.
To Complete the IMAGE *LOCK This command places a logical lock on the
Command :D-traindb :R-product product data set in the traindb database.
Each HP ALLBASE/4GL item reference is
prefixed by a colon (:).
The logical lock is a normal HP
TurboIMAGE/iX lock, where the lock
descriptors are stored in a table. All new
lock requests are compared with the
descriptors currently in the table. If the
descriptor already exists in the table, the
new lock is denied; otherwise it is
granted.
The lock does not check to ensure whether
any records with the product number
specified exist.
This lock is maintained until the DM IMAGE
*UNLOCK command is executed in the
product_proc process.
To complete this command:
1. Press Commit Data .
When you press this key, HP ALLBASE/4GL clears the window and displays
the entered command at the first line of the function.
To enter the next command:
Field Entry Explanation
---------------------------------------------------------------------------------------
Step Number Accept the default.
Action Accept the default. Again you will see the FILE window appear.
The window is exactly the same as the one
you used when you were defining the
process.
File Operation *READ This time you want to read a record from
the file. You can enter this command as
READ without the asterisk.
*NOLOCK Accept the default.
File ID[.Record] product Again, this is a reference to the default
record layout on the product file.
*INDEX= Leave blank. This field allows you to specify which
index is used to access the file. Leaving
it blank means that the file is accessed
using the index specified by the current
value in the communication area field
*INDEXNO.
HP ALLBASE/4GL initializes the value in
*INDEXNO to 1 when an application starts,
assuming that all file access is to be via
the primary key.
*KEY= * This clause specifies the value to be moved
to the key field of the file buffer before
the file read is performed.
The * refers to the contents of the current
field (product_no) on the data screen.
If you don't specify a key, the file read
takes place using the current contents of
the key field in the file buffer.
To complete this command:
1. Press Commit Data .
When you press this key, HP ALLBASE/4GL clears the window and displays
the entered command at the second line of the function. You will see
that the *KEY= * clause is included in the command line.
To enter the next command:
Field Entry Explanation
---------------------------------------------------------------------------------------
Step Number Accept the default.
Action Accept the default.
Command SHOW
To Complete the *REFRESH Notice that you can enter either lowercase
Command or uppercase characters for the word
REFRESH. This command redisplays the fields
on the screen. The *REFRESH clause
specifies that data is moved from the data
movement fields to the internal screen
buffers before the fields are redisplayed.
All the fields on the screen have been
created with primary movement fields from
the product file. This means that the
current contents of the file buffer are
displayed by this command.
To complete this command:
1. Press Commit Data .
HP ALLBASE/4GL displays the new command line and clears the window. This
function is now complete.
Now you can generate the function. This procedure is the same for all
data managers.