Difference between LOV and list item

• LOVs open in a separate window , list items are positioned on a canvas
• LOVs are suited for many rows, list items should be limited to 15 rows.
• LOVs show multiple columns, list items show only one.

SHOW_LOV built in

SHOW_LOV built in is also used to display LOV , but its functionality is slightly different from the at of LIST_VALUES. It does not require that the LOV be attached to an item and it allows you to call an LOV explicitly by name.

LIST_VALUES built in

o LIST_VALUES displays the list of values for the current item, as long as the input focus is in a text item that has an attached LOV. Will only work if there is an LOV attached to the current item. The cursor must be in an item that has an LOV attached to it for LIST_VALUES to work. If we put LIST_VALUE inside when_button_presses an error is reported, if we want to put LIST_VALUES inside a button we need to have the Mouse Navigate Property set to NO so Oracle forms won’t perform navigation to the item when the end user activates the item with a mouse in this case of click on the button the triggers WHEN-BUTTON-PRESSED will fire but the input focus remains in the current item.
 It has the parameters NO_RESTRICT: Specifies that Oracle Forms will not use the automatic search and complete feature.
 Restrict: Specifies that Oracle Forms will use the automatic search and complete feature.

Set LOV properties

o Column Mapping Properties: Defines which columns will be displayed and each column’s return item (which item on the form the LOV column will populate_ and the width and title for the LOV column.
o Automatic Refresh Property: to refresh the record group data before displaying LOV.
o Filter Before display: If set to Yes, this property will present the user with a small filter window to let them filter the values returned to the LOV.
o Automatic Position property will positions the LOV just below the item that the LOV is attached to.

LOV Wizard to create an LOV

• We can access the LOV wizard by selecting Tools – LOV Wizard from the main menu.
• The wizard will create the objects that comprise an LOV and will adjust the properties of these objects.
• The wizard only creates record groups based on queries; it cannot help you define static record groups.
• The wizard pages are:
• Source Page: the wizard will create a record group object along with the LOV object.
• SQL Query Page: The wizard will take the query you have written here and store it the record group’s.
• Column Selection Page: Begin to populate the new LOV’s Column Mapping Properties.
• Column Display Page: Populate the LOV’s Column mapping properties.
• Advanced Options Page: The wizard will set the Record Group Fetch Size property for the record group. It will also set the Automatic Refresh property ofr the LOV. It can also set the Filter Before Display property for the LOV.
• Items Page: The wizard will set the List of Values property to the item.
• Automatic Display Property will display the LOV as soon as the user navigates into it.

Design, create and associate LOV’s with text items in a form module

Each column in the LOV can be “linked” to a displayed field so that when the LOV item is selected, it can populate a number of fields on screen. Each column in the LOV can return to only one field in the form. When one of the values of the LOV is returned to the form, you have the option to “attaché the LOV to one of the fields so the users can invoke the list to select a value. An LOV is assigned to a text item in the form by setting the following properties:
List of values: Which LOV to associate with this item.
List X Position/ List Y position Specific location to display LOV are relative to the entire screen
Validate from list: Indicates that the LOV should be used to determine that the data entered into the field is valid. When data is typed into the field, the LOV is consulted to determine if the value entered is included in the LOV. For this property to work, the first column of the LOV must be the column that is bound to the form item.
It’s possible to configure an LOV so that it is not attached to a specific item and is available no matter where the user has navigated.
List of Values appears on the status line whenever an LOV is available to the current text item.

Relationship between LOVs and record groups

• All LOVs are based on another Forms object called a record group.
• Record groups are logical objects, so they have no physical properties and are never displayed to the user.
• A record group is similar to a database table in that it stores an array of values in a column and row format.
• Record groups belong to a form and are stored locally on a user’s machine rather that in a database instance.
• The group’s structure can be defined in three ways: by query at design-time, statically at design time, programmatically at run time.
• We can have multiple LOV based on the same record group.
• You should not put a semi colon after the query in the record group.

LOV

List-of-values displays a pop-up listing of available values for a form field. It’s based on record group.
LOVs serve a number of purposes. They make data entry easier, and they ensure the validity of data.