validation

making sure data is sensible, reasonable, complete and within reasonable boundries. it reduced the number of errors when data is entered into a system

range check

• used when data consists of numbers, currency, or date/time. it allows you to set suitible boundries
• example: shoe sizes in stock>=4AND<=9

type check

• ensures the correct type of data is entered into that field
• example: dress sizes range from 8 to 18. by setting the data type to number only numbers can be entered as dress sizes so the written equivelant of the number can't be entered such as 'ten' instead of 10

check digit

• used when you want to be  sure that a range of numbers was entered correctly
• example: checking…