Data Inputting
- Three types of data inputting; manually, using form and scanning.
- Three possible types of errors
o Data entry errors
Omission error – Something is left out. Ex: _ello instead of hello
Substitution error – Something is replacing in error Ex: nello instead
of hello
Transposition error – Two things are replaced in error Ex: holle
instead of hello
Verification and Validation
Verification to be done after inputting
o Visual checking -> Manually check the data is correct
o Double entry -> Data is entered twice (Eg: passwords on
signup)
Validation to be done before inputting
o Range check -> Sets minima and maxima for entered data
o Type check -> Check that the type of data is correct (int,
String)
o Presence check -> Checks that data is actually entered
o Length check -> Checks that data is of a particular length
o Picture check -> Check that format of data is correct
o Consistency -> Checks that data corresponds between
specific fields
o Control data -> Verify the actual ammounts of input is as
should be
o Check digit verification -> Numerical input with a sum being
worked on with the answer validating the input
o Hardware errors
Power cuts
Prevention via UPS
Hardware corruption
Prevention via on-site backups
o Programming errors
Syntax errors
Ex: Forgetting to close curly brackets, forgetting semicolon
Prevention via translator debugger
Logic error
Ex: Syntax is correct but programming logic to achieve goal is wrong
Dry run and trace facilities1
Runtime error
Ex: Using a 6th position in a 5 letter array, dividing by zero
Dry run and trace facilities
1
Programs that indicated the exact path taken by the computer during the execution
- Three types of data inputting; manually, using form and scanning.
- Three possible types of errors
o Data entry errors
Omission error – Something is left out. Ex: _ello instead of hello
Substitution error – Something is replacing in error Ex: nello instead
of hello
Transposition error – Two things are replaced in error Ex: holle
instead of hello
Verification and Validation
Verification to be done after inputting
o Visual checking -> Manually check the data is correct
o Double entry -> Data is entered twice (Eg: passwords on
signup)
Validation to be done before inputting
o Range check -> Sets minima and maxima for entered data
o Type check -> Check that the type of data is correct (int,
String)
o Presence check -> Checks that data is actually entered
o Length check -> Checks that data is of a particular length
o Picture check -> Check that format of data is correct
o Consistency -> Checks that data corresponds between
specific fields
o Control data -> Verify the actual ammounts of input is as
should be
o Check digit verification -> Numerical input with a sum being
worked on with the answer validating the input
o Hardware errors
Power cuts
Prevention via UPS
Hardware corruption
Prevention via on-site backups
o Programming errors
Syntax errors
Ex: Forgetting to close curly brackets, forgetting semicolon
Prevention via translator debugger
Logic error
Ex: Syntax is correct but programming logic to achieve goal is wrong
Dry run and trace facilities1
Runtime error
Ex: Using a 6th position in a 5 letter array, dividing by zero
Dry run and trace facilities
1
Programs that indicated the exact path taken by the computer during the execution
