Chapter 5 BC Introduction to Forms Builder Tiggers

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

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 usingle table] • Create a master-detail form that contains multiple data blocks [Done in Oracle Lab 7] • Format form text items using format masks 2

Using Format Masks to Format Character Strings • Format mask – Same as format model – Set using Property Palette – Proceeded by FM 999. 99 : for numeric fields MM/DD/YYYY : for dates • 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 3

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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 foreign key values • Describe the different form items that you can use to enter and modify data values 5

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 6 record

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. 7

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 8

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 9

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

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 form text item • Record group – Form object that represents data in tabular format – Provides values for LOV 11

Creating a List of Values (LOV) Show (p. 364 -376) GO_ITEM(‘block_name. item_name); LIST_VALUES; GO_ITEM(‘student. f_id); LIST_VALUES; 12