Remove a Book

Removing a Book

Interface Definitions:

Inputs to module:

• Call Number of the library book to be removed.

Inputs by user:

• Name of the Book.
• Publisher of the book.
• Year published of the book.

Outputs:

• Confirmation message

"Removing will result in loss of book information. Proceed with Remove?"

Data Abstractions:

CALL NUMBER is a positive integer number.

NAME is a variable length string.

PUBLISHER is a variable length string.

YEAR OF PUBLISHED is a fix length digit string.

Design:

Environment: GUI (graphical user interface)

Interface: Pop-up window. (See picture files for a view.)

• Every item from Data Abstraction will be entered in it's own text-box.
• These text-boxes will allow strings larger than the text-box size to be entered.
• The remove will be a batch process. i.e. none of the book will be removed until the remove-Book button/key is activated.
• When the button/key is entered certain items will be checked for syntactical errors (for errors see ERROR HANDLING).
• CALL NUMBER will be checked against existing call number.
• NAME will be checked against existing name.
• PUBLISHER will be checked against existing publisher.
• YEAR OF PUBLISHED will be checked against existing year of published.
  

Completion of this module is performed by:

1. Pressing Cancel - in which case no remove is performed.
   • Remove window is closed.
2. Pressing Remove - syntactical error checking is done.
   • Confirmation Window is popped up.

At Confirmation Window:

1. Pressing Cancel - no remove is performed.
   • Confirmation Window is closed.
2. Pressing Remove - remove information.
   • Confirmation Window is closed.
   • Remove window is closed.
   • It will be possible to for user to interrupt this module and do something else. BUT the system cannot close without explicitly completing this module.

Sub-Modules:

• None.

• Error Handling:

Syntactical Errors:

• IF call number entered does not match any call number currently in system.

THEN give error window:

Text-Box: "Call number is unknown, is the typing correct?"

Buttons: CORRECT, CANCEL

Actions: CORRECT

• Change call number.
• Close window.
• Continue error checking.

CANCEL

• Close window.
• Cancel all completion procedures.
• Return to Remove Window.

• IF name entered does not match any name currently in system.

THEN give error window:

Text-Box: "Name is unknown, is the spelling correct?"

Text-Box: A similarly spelled name (lexicographically) is displayed.

Buttons: CORRECT, CANCEL

Actions: CORRECT

• Change name to suggested one.
• Close window.
• Continue error checking.

CANCEL

• Close window.
• Cancel all completion procedures.
• Return to Remove Window.

• IF publisher entered does not match any format currently in system.

THEN give error window:

Text-Box: "Name of publisher is unknown, is it correct?"

Buttons: CORRECT, CANCEL

Actions: CORRECT

• Change name to suggested one.
• Close window.
• Continue error checking.

CANCEL

• Close window.
• Cancel all completion procedures.
• Return to Remove Window.

• IF year published entered does not match any format currently in system.

THEN give error window:

Text-Box: "Format of year published is unknown, is it correct?"

Buttons: CORRECT, CANCEL

Actions: CORRECT

• Change year published to the correct one.
• Close window.
• Continue error checking.

CANCEL

• Close window.
• Cancel all completion procedures.
• Return to Remove Window.

Empty-Field Errors:

• IF CALL NUMBER field is left empty

THEN give error window:

Text-Box: "A call number MUST be entered!"

Buttons: ADD, CANCEL

Actions: ADD

• Add call number.
• Close window.
• Continue error checking.

CANCEL

• Close window.
• Cancel all completion procedures.
• Return to Remove Window.
• For every other field

• IF field is left empty

THEN give error window:

Text-Box: "Field - "(insert fields name here) "was left empty."

"Continue anyway?"

Buttons: YES, CANCEL

Actions: YES

• Keep blank field.
• Close window.
• Continue error checking.

CANCEL

• Close window.
• Cancel all completion procedures.
• Return to Remove Window.

Imports:

• Library book's information is retrieved from the database on entry into this module.

Exports:

• Library book's information is removed from the database.

Pseudocode/Visual Basic Code

PSEUDOCODE : Remove Book.

///Opening Window
// User inputs the call number for the book here
 

//  Validation sees if the call number is a valid one or 
//  not

Validation (Call Number)
read (button)

  IF button is Ok then
  	check (Call Number)
		If Call number is Valid then 
		   Process (Call Number)    
		Else  
		   Output Error Message
		   read (Call Number)
	           Validation (Call Number)
  Elsif button is Cancel
  	EXIT
  END;
End Validation.

// Process actually processes the user request for 
// deletion of a book unless a cancel is inputed
 Process (Call Number)

 IF Book [Call Number].status = on loan THEN
	output Error message
 	EXIT
 ELSE
  	Output Book information
	Output Confirmation message
	read (User confirmation)
		If User Confirmation = Ok
		  Remove (Book)
		  Output (Success in deleting book)
		Else
		  Output (No changes made)
		  EXIT
		END
 END


 END Process.

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