Chapter 6: Creating Custom Forms

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Chapter 6 Creating Custom Forms

• Guide to Oracle 10g

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Lesson C Objectives

• After completing this lesson, you should be able
  to
• Convert data blocks to control blocks
• Link data blocks to control blocks
• Create a form that has multiple canvases
• Create tab canvases
• Create stacked canvases

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Converting a Data Block to a Control Block

• Use Data Block and Layout Wizards to create data
  block form and form layout
• Convert data block to control block
• Add command buttons to control form processing
• Simplify creation of control blocks

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Converting a Data Block to a Control Block
(continued)

• To convert data block to control block
• Change data blocks Database Data Block property
  value to No
• Change Required property value of text item that
  represents data block tables primary key to No

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Linking a Data Block to a Control Block

• Create forms that link data blocks and control
  blocks to work together
• Usually represent master-detail relationship

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Creating the Data Block

• Use Data Block Wizard and Layout Wizards
• To create and configure data block
• Must contain field that links it to control block
• Create data block without master-detail
  relationship
• Link two blocks later

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Linking the Control Block and the Data Block

• Open detail data blocks Property Palette
• Modify data blocks WHERE Clause property
• General syntax
• fieldname control_block.text_item_name

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Refreshing the Data Block Values

• Add commands to
• Initially populate data block display
• Periodically refresh data block records
• Use the GO_BLOCK built-in
• To move form focus to data block
• Then execute EXECUTE_QUERY built-in
• Flushes block
• Makes information consistent with corresponding
  database data

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Creating Forms with Multiple Canvases

• Good practice not to show too much information on
  users screen display
• Single-form approach
• Create one form with multiple canvases
• Enables form to share data among different
  canvases
• Impossible for multiple programmers to work
  simultaneously on different canvases of same
  application

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Creating Forms with Multiple Canvases (continued)

• Multiple-form approach
• Create multiple forms with different .fmb file
  for each application canvas
• Works well when multiple programmers collaborate
  to create complex application
• Enables programmers to use form in many different
  applications
• More difficult for related forms to share data

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The Northwoods University Student Services Process

• Identify sequence of actions that user will
  employ to interact with canvases

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Interface Design

• Student Log On canvas
• Menu canvas
• Student Information canvas
• Course Grades canvas
• Enrollment canvas

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Working with Multiple Canvases and Data Blocks

• Create form that contains multiple canvases
• Create individual canvases
• Specify to display specific block items on
  specific canvas
• Create new data block
• Select canvas name on which block items appear
• On Layout Wizard Canvas page

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Working with Multiple Canvases and Data Blocks
(continued)

• Often forms that have multiple canvases also have
  multiple data blocks
• Group items that appear on same canvas in single
  data block
• To keep blocks small and manageable
• Cannot create two items that have same name in
  same data block
• Ensure that Forms Builder places new items in
  correct block

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Specifying the Block Navigation Order

• Specify which canvas initially appears when user
  runs form
• Canvas whose block items appear first under Data
  Blocks node in Object Navigator window
• Order of canvases in Object Navigator Canvases
  list does not matter
• Only order of data blocks

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Object Navigator
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Referencing Different Canvases, Form Blocks, and
Block Items

• All form items have Canvas property
• Specifies name of canvas on which item appears
• Form always displays canvas on which item with
  focus appears
• Execute GO_ITEM built-in
• Move form focus to item on target canvas
• Good practice to include block name

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Creating and Configuring Tab Canvases in Forms

• Tab canvases
• Multiple-page canvases
• Allow users to move between multiple canvas
  surfaces
• By selecting tabs at top of canvas
• Display large number of related items in modular
  way
• Direct user through sequence of steps for
  performing task

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Creating a Tab Canvas

• Contains two or more tab pages
• Tab page
• Object representing surface
• Displays form items
• Has tab label identifier at top

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Creating a Tab Canvas (continued)

• Create form that contains tab canvas
• Create form
• Create new content canvas in form
• Create tab canvas on content canvas
• Configure tab pages

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Creating Form Items on a Tab Canvas

• Use tab pages as any content canvas
• Create items on tab pages
• Using Data Block Wizard
• By creating control block and drawing text items
  directly on tab canvases
• Must be sure to specify placement of items on tab
  canvas

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Lesson C Summary

• Convert data block to control block
• Create relationship between control block and
  data block
• Display information on multiple canvases
• Single-form approach
• Multiple-form approach
• Tab canvas
• Multiple-page canvas

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Summary

• Custom form
• Runtime errors
• Forms Debugger
• Form triggers
• Create custom messages and alerts
• Validate user inputs

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Summary (continued)

• Convert a data block to a control block
• Create relationship between control block and
  data block
• Display information on multiple canvases
• Tab canvas