Suposeu que feu servir un full de càlcul i que us cal canviar l' adreça d' almenys una persona. Teniu un petit problema: sovint heu de canviar l' adreça en moltes línies. Per exemple, Joana agafa tres línies. Tindreu un bon problema si oblideu de canviar alguna de les línies - l' adreça assignada a aquella persona serà ambígua, per tant les vostres dades perden integritat.
Suppose you are using a spreadsheet and you need to change the address of at least one person. You have a small problem: you often have to change the address in many rows. For example, Joan takes three rows. A real problem will arise if you forget to change one of the rows - the address assigned to this person will be ambiguous, hence your data loses integrity.