System Variables

System Variables:

System variables are oracle form variables that is used to control the way an application behaves.

List of system Variables:

1)      System.Form_Status

2)      System.Block_Status

3)      System.Record_Status

4)      System.Coordination_Operation

5)      System.Master_Block

6)      System.Current_Block

7)      System.Current_Form

8)      System.Current_Item

9)      System.Current_Value

10)  System.Cursor_Block

11)  System.Cursor_Record

12)  System.Cursor_Item

13)  System.Cursor_Value

14)  System.Last_Form

15)  System.Last_Record

16)  System.Last_Query

17)  System.Message_Level

18)  System.Suppress_Working

19)  System.Mode

Synchronize Built-in

SYNCHRONIZE built-in:

SYNCHRONIZE built-in is used to synchronize the Terminal Screen with the internal state of the form.

SYNCHRONIZE update the screen display to reflect the information that Form Bulder has its internal representation of the screen.

Example:

                        BEGIN

FOR J IN 1..1000 LOOP

:Control.Id:=J;

SYNCHRONIZE;

Process_Element(J);

END LOOP;

END;

Open_Form, Call_Form and New_Form

Multiple Forms can be invoked in an application through three built-in:

1)      OPEN_FORM

2)      CALL_FORM

3)      NEW_FORM

OPEN_FORM:

OPEN_FORM opens another form in a modeless window. The user can work on Multiple forms concurrently. The user can navigate within multiple forms.

With the OPEN_FORM the user can call another form in a different database session.

Syntax: OPEN_FORM (‘form_name’, active_mode, session_mode, data_mode, paramlist);   Default:   activate and no session mode.

OPEN_FORM is a restricted procedure and cannot be called in the Enter-Query mode.

CALL_FORM:

CALL_FORM calls another form in a Modal window. The user cannot navigate within different Forms. Requires to exit the called form before navigating back to the calling form. Forms are called in the same session.

NEW_FORM:

NEW_FORM exits the current form and opens the new form as a parent window.

NEW_FORM releases the memory by exiting the current form.

Benefits of Multiple form Applications are:

Easier to debug small form.

Flexibility between forms.

Easy to maintain.

Modularity.

Data can be exchanged between forms.

LOV (List Of Values)

LOV (List of Values):

An LOV is a scrollable popup window with either single or multi-column selection list.

Types of LOV:

Static LOV: Contains the predetermined values.

Dynamic LOV: Contains values that come at runtime.

LOV for Validation property of an item:
When LOV for validation is set to true, Oracle forms compares the current value of the text item to the values in the first column displayed in the LOV whenever the validation event occurs. If the value in the text item matches one of the values in the first column of LOV, validation succeeds, the LOV is not displayed and the processing continues normally. If the value in the text item does not match one of the values in the first column of the LOV, Oracle forms displays the LOV and uses the text item value as the search criteria to automatically reduce the list.

Built-in used to display the LOV are:

SHOW_LOV (Function)

LIST_VALUES (Procedure)

Built-in that are used for setting the LOV properties:

SET_LOV_PROPERTY

GET_LOV_PROPERTY