Transcript CH6_A
Creating Custom Forms Part A Eyad Alshareef 1 Data Block and Custom Forms Data block form Based on data blocks that are associated with specific database tables Reflect the structure of the database Custom form Based on control blocks that process data from multiple tables Reflect business processes rather than the database structure Eyad Alshareef 2 Introduction to Custom Forms Custom form Displays data fields from variety of database tables Contains programs that support organizational processes Use lists of values (LOVs) to retrieve data values Manipulate data using form triggers Eyad Alshareef 3 Identifying the Business Processes and Database Operations Identify processes that form supports Identify associated database tables Describe process Eyad Alshareef 4 Designing the Interface Visualize how form will look Eyad Alshareef 5 Creating a Custom Form Manually create form canvas in Object Navigator Create form items by “painting” items on canvas Using tools on Layout Editor tool palette Write code that controls form functions Eyad Alshareef 6 Creating the Form Canvas Manually create form canvas in Object Navigator Start Forms Builder Create and rename form canvas Rename form module and form window Change Title property of form window Perform in Visual View in Object Navigator Eyad Alshareef 7 Creating a Control Block Control data block Also called control block Data block not associated with particular database table Create new data block in Object Navigator Specify data block created manually Use Ownership View Eyad Alshareef 8 Creating the Form Items Create Boilerplate logo image and text Form text items Command button items Display form in Layout Editor Draw items on form canvas using tools in tool palette Eyad Alshareef 9 Creating the LOVs LOV Retrieve data from database table Use LOV Wizard Run form To test LOV Eyad Alshareef 10 Displaying System Date and Time Values in Form Text Items System variable Variable representing value always available to any form Display value in text item automatically Set text item’s Initial Value property Eyad Alshareef 11 Forms Builder Date and Time System Variables Eyad Alshareef 12 Creating Command Buttons Create and configure buttons Create form triggers associated with buttons Eyad Alshareef 13 Creating and Configuring Command Buttons Draw button on canvas using Button tool Button tool on tool palette Button group Buttons should all be same size Wide enough to accommodate longest button’s label Draw button with longest label first Eyad Alshareef 14 Creating the Button Triggers Select Triggers node under button in Object Navigator Click Create button to create trigger Select trigger event Specify trigger code WHEN-BUTTON-PRESSED button event Trigger code executes when user clicks button Eyad Alshareef 15 Creating the Button Triggers (continued) Reference form items: :block_name.item_name Clear form text items in form trigger: Use CLEAR_FORM built-in procedure Create program unit to set value of text items to blank text string Procedure Code block that executes commands to change one or more values Eyad Alshareef 16 Creating the Button Triggers (continued) Function Code block Returns single value Create program unit: Open Object Navigator Select Program Units node Click Create button Program unit does not use DECLARE keyword Eyad Alshareef 17 Creating a Custom Form 1. 2. 3. Create the form Create the form window and canvas manually Create a control block 4. Data block that is not associated with a specific table Contains form items that you manually draw on the canvas Create form triggers to process data Eyad Alshareef 18 Form Triggers Code that is associated with a form object and an event Can contain SQL INSERT, UPDATE, DELETE, and SELECT commands Referencing form text item values in triggers: :block_name.item_name Eyad Alshareef 19 Practice1 Create a custom form that has: Employee Name Employee Salary Department Name Create a LOV to retrieve block records Use triggers to retrieve block records Create a button that calls a program unit to clear the block. Eyad Alshareef 20 Creating a custom form Create a new form module and name it COURSE Click on data bloc and then on the plus icon. Select Build a data block manually Rename your block into COURSE_BLOCK Eyad Alshareef 21 Create and modify a canvas Add a canvas by clicking on Canvas in object navigator and then on a plus sign Rename your canvas into HEADER, and open it with Design Editor Eyad Alshareef 22 Create and modify a canvas Change the background color of the canvas using the Property palette Add a header “Course Information” Add a picture (download any picture from the web, save in in C:\\temp, then go to Edit, Import) Eyad Alshareef 23 Add text boxes and prompts Using the toolbox on the left, add Course Name text box and a corresponding prompt: Eyad Alshareef 24 Add text boxes and prompts Using the toolbox, add a stacked canvas on COURSE canvas Name your canvas COURSE_ITEMS Add Room and Time text boxes and corresponding prompts to the COURSE_ITEMS canvas Eyad Alshareef 25 Add control buttons Return to the main canvas Using toolbox on the left, add four control buttons. Name them New, Find, Save and Clear Eyad Alshareef 26 Adding PL/SQL code Create triggers for each of the buttons Add PL/SQL code to the triggers Eyad Alshareef 27 Adding PL/SQL code Eyad Alshareef 28 Adding PL/SQL code Create triggers for each of the buttons Add PL/SQL code to the triggers Eyad Alshareef 29 Adding PL/SQL code Create triggers for each of the buttons Add PL/SQL code to the triggers Eyad Alshareef 30 Adding PL/SQL code Create triggers for each of the buttons Add PL/SQL code to the triggers Eyad Alshareef 31 Form Trigger Properties Trigger activated In response to event such as clicking button Trigger name defines event that activates it Eyad Alshareef 32 Trigger Categories Eyad Alshareef 33 Trigger Timing Specifies when trigger fires PRE POST Fire just before event successfully completes Fire just after event successfully completes ON-,WHEN-, and KEY Fire in response to actions Eyad Alshareef 34 Trigger Scope Defines where event must occur in order for associated trigger to fire Includes object to which trigger attached And objects within trigger object Eyad Alshareef 35 Trigger Execution Hierarchy Defines which trigger fires When object within form object contains same trigger that form object contains By default trigger in higher-level object overrides trigger in lower-level object Can specify custom execution hierarchy Eyad Alshareef 36 Directing Form External Navigation External navigation Form focus User causes form focus to change by making different form item active Item currently selected on form Internal navigation Result of internal form code that responds to external navigation operations or trigger commands Eyad Alshareef 37 Setting the Form Tab Order Set tab order Place items in correct order under Items node In Object Navigator window Eyad Alshareef 38 Directing External Navigation Using Built-in Subprograms Built-in subprograms Called built-ins Use to direct external form navigation Cannot use in navigational triggers Eyad Alshareef 39 Built-in Subprograms to Control External Navigation Eyad Alshareef 40 Triggers That Fire at Form Startup Triggers Fired User Action 1 2 PRE-FORM PRE-BLOCK User starts form 4 Result on User Screen Display 3 Form appears, but with no data visible 5 WHEN-NEW-FORM-INSTANCE WHEN-NEW-BLOCK-INSTANCE WHEN-NEW-RECORD-INSTANCE WHEN-NEW-ITEM-INSTANCE Eyad Alshareef Form is available for use 41 Triggers That Fire as a Result Of External Navigation User Action User places the insertion point in a text item User clicks the Next Record button Triggers Fired WHEN-NEW-ITEM-INSTANCE WHEN-NEW-RECORD-INSTANCE WHEN-NEW-ITEM-INSTANCE Eyad Alshareef Result on User Screen Display Insertion point appears in item Next record appears 42 Triggers That Fire When a Form Closes User Action User closes the Forms Runtime window Triggers Fired POST-BLOCK POST-FORM Eyad Alshareef Result on User Screen Display Forms Runtime window closes 43