In the relational data model, entity integrity is one of the three inherent integrity rules. Entity integrity is an integrity rule which states that every table must have a primary key and that the column or columns chosen to be the primary key should be unique and not null.
Within relational databases using SQL, entity integrity is enforced by adding a primary key clause to a schema definition. The system enforces Entity Integrity by not allowing operation (INSERT, UPDATE) to produce an invalid primary key. Any operation that is likely to create a duplicate primary key or one containing nulls is rejected. The Entity Integrity ensures that the data that you store remains in the proper format as well as comprehensible.
Famous quotes containing the words entity and/or integrity:
“What is this world of ours? A complex entity subject to sudden changes which all indicate a tendency to destruction; a swift succession of beings which follow one another, assert themselves and disappear; a fleeting symmetry; a momentary order.”
—Denis Diderot (1713–1784)
“In no nation are the institutions of progress more advanced. In no nation are the fruits of accomplishment more secure. In no nation is the government more worthy of respect. No country is more loved by its people. I have an abiding faith in their capacity, integrity and high purpose. I have no fears for the future of our country. It is bright with hope.”
—Herbert Hoover (1874–1964)