Oracle 10g Forms Lesson 13
- 2. Objectives After completing this lesson, you should be able to do the following: Define triggers Identify the different trigger categories Plan the type and scope of triggers in a form Describe the properties that affect the behavior of a trigger
- 3. Trigger Overview Event Trigger types Queries Validation Navigation Interaction Internal event Errors/Messages Others PL/SQL Fire PL/SQL PL/SQL Which trigger would you use to perform complex calculations after a user enters data into an item?
- 4. Grouping Triggers into Categories Triggers may be grouped into functional categories: Block processing triggers Interface event triggers Master-detail triggers Message handling triggers Navigational triggers Query-time triggers Transactional triggers Validation triggers Triggers may be grouped into categories based on name: When-Event triggers On-Event triggers Pre-Event triggers Post-Event triggers Key triggers
- 6. Defining Trigger Components What event? What action? What level? Type Code Scope
- 7. Trigger Type Pre- Post- When- On- Key- User-named What event? Type Code Scope
- 8. Trigger Type Forms Builder Trigger Types
- 9. Trigger Code Statements PL/SQL User subprograms Built-in subprograms Type Code Scope What action?
- 10. Trigger Scope Levels Form Block Item Code Scope Type What level?
- 11. Trigger Scope Event Event Event Order Date
- 12. Specifying Execution Hierarchy Form level Block level Item level On-Message On-Message On-Message On-Error On-Error EH = After EH = After EH = Before EH = Override 1 2 3 4 Event Event
- 14. Summary In this lesson, you should have learned that: Triggers are event-activated program units You can categorize triggers based on function or name to help you understand how they work Trigger components are: Type: Defines the event that fires the trigger Code: The actions a trigger performs Scope: Specifies the level (form, block, or item) at which the trigger is defined The Execution Hierarchy trigger property alters the firing sequence of a trigger