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Chapter 5B-C: Introduction to Forms Builder:
Tiggers, LOV
2
Lesson B Objectives
After completing this lesson, you should be able to:• Create a data block form that is based on a
database view [Same as using single table]• Create a master-detail form that contains multiple
data blocks [Done in Oracle Lab 7]• Format form text items using format masks
3
Using Format Masks to Format Character Strings
• Format mask – Same as format model– Set using Property Palette– Proceeded by FM
• Example of format mask for phone number:FM “(”999“)”999“-”9999
• To set the format mask– Open the form in the Layout Editor– Select the text item you want to apply the format to– Right-click and select Property Palette– In the Data property node, type the mask in the Format Mask
text box
999.99 :for numeric fieldsMM/DD/YYYY : for dates
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Lesson C Objectives
After completing this lesson, you should be able to:• Use sequences to automatically generate primary
key values in a form• Create lists of values (LOVs) to provide lists for
foreign key values• Describe the different form items that you can use
to enter and modify data values
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Using Sequences to Generate Primary Key Values
• Users may make mistakes entering primary key values
• Use sequence to generate key– Create sequence in database– Create a trigger (PL/SQL program)
• that you link to the text item object representing the primary key value on a form
• that inserts the primary key value from the sequence when a user takes action to create a new record
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Creating Form Triggers
• Form trigger – Program unit in form that runs in response to event
– Associated with form object
• Event
– User action like clicking a button
– System action like loading or exiting a form
• Trigger firing means …– The trigger runs.
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Creating Form Triggers• Built-in events that can be associated with form triggers
• The triggers to be written in PL/SQL editor will fire when event occurs
Triggers dialog box showing block events that can be associated
with triggers
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Creating Form Triggers (continued)
• Implicit cursor can be used to retrieve the next sequence value into a form’s text item
• General syntaxSELECT field_name
INTO variable_name
FROM table_name
WHERE search condition;
• Syntax for retrieving next sequence value into the form’s loc_id text item
SELECT loc_id_sequence.NEXTVALINTO :location.loc_idFROM dual;
• loc_id_sequence must be created in the database
• : must be added to refence a form’s text item in PL/SQL
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Create a trigger for inserting loc_id when a new record is to be created using
location.fmb
Show how (p. 354-360)
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Creating a List of Values (LOV)
• List of values (LOV)– Pronounced ell-oh-vee
– Displays list of possible data values for text item
• LOV display – Dialog box displays possible choices for form
text item
• Record group– Form object that represents data in tabular
format
– Provides values for LOV
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Creating a List of Values (LOV)Show how (p. 364-376)
GO_ITEM(‘block_name.item_name);LIST_VALUES;
GO_ITEM(‘student.f_id);LIST_VALUES;