Referential integrity is a property of data which, when satisfied, requires every value of one attribute (column) of a relation (table) to exist as a value of another attribute in a different (or the same) relation (table).
For referential integrity to hold in a relational database, any field in a table that is declared a foreign key can contain only values from a parent table's primary key or a candidate key. For instance, deleting a record that contains a value referred to by a foreign key in another table would break referential integrity. Some relational database management systems (RDBMS) can enforce referential integrity, normally either by deleting the foreign key rows as well to maintain integrity, or by returning an error and not performing the delete. Which method is used may be determined by a referential integrity constraint defined in a data dictionary.
Famous quotes containing the word integrity:
“I condemn Christianity. I raise against the Christian church the most terrible accusation that any accuser has ever uttered. It is to me the ultimate conceivable corruption. It has possessed the will to the final corruption that is even possible. The Christian church has left nothing untouched by its depravity: it has turned every value into a disvalue, every truth into a falsehood, every integrity into a vileness of the soul.”
—Friedrich Nietzsche (1844–1900)