1. Chapter 5B-C: Introduction to Forms Builder: Tiggers, LOV

2. 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. 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 fields MM/DD/YYYY : for dates

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5. 5 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

6. 6 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

7. 7 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.

8. 8 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

9. 9 Creating Form Triggers (continued) Implicit cursor can be used to retrieve the next sequence value into a form’s text item General syntax SELECT 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.NEXTVAL INTO :location.loc_id FROM dual; loc_id_sequence must be created in the database : must be added to refence a form’s text item in PL/SQL

10. 10 Create a trigger for inserting loc_id when a new record is to be created using location.fmb Show how (p. 354-360)

11. 11 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

12. 12 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;