Editing Database design (section)

=== Determining data relationships ===
Once a database designer is aware of the data which is to be stored within the database, they must then determine where dependency is within the data. Sometimes when data is changed you can be changing other data that is not visible. For example, in a list of names and addresses, assuming a situation where multiple people can have the same address, but one person cannot have more than one address, the address is dependent upon the name. When provided a name and the list the address can be uniquely determined; however, the inverse does not hold – when given an address and the list, a name cannot be uniquely determined because multiple people can reside at an address.  Because an address is determined by a name, an address is considered dependent on a name.

(NOTE: A common misconception is that the [[Relational models theory|relational model]] is so called because of the stating of relationships between data elements therein. This is not true. The relational model is so named because it is based upon the mathematical structures known as [[Relation (mathematics)|relations]].)