Check Constraint - Definition

Definition

Each check constraint has to be defined in the CREATE TABLE or ALTER TABLE statement using the syntax:

CREATE TABLE table_name ( ..., CONSTRAINT constraint_name CHECK ( predicate ), ... ) ALTER TABLE table_name ADD CONSTRAINT constraint_name CHECK ( predicate )

If the check constraint refers to a single column only, it is possible to specify the constraint as part of the column definition.

CREATE TABLE table_name ( ... column_name type CHECK ( predicate ), ... )

Read more about this topic:  Check Constraint

Famous quotes containing the word definition:

    “It is very hard to give a just definition of love. The most we can say of it is this: that in the soul, it is a desire to rule; in the spirit, it is a sympathy; and in the body, it is but a hidden and subtle desire to possess—after many mysteries—what one loves.”
    —François, Duc De La Rochefoucauld (1613–1680)

    “The man who knows governments most completely is he who troubles himself least about a definition which shall give their essence. Enjoying an intimate acquaintance with all their particularities in turn, he would naturally regard an abstract conception in which these were unified as a thing more misleading than enlightening.”
    —William James (1842–1910)

    “Mothers often are too easily intimidated by their children’s negative reactions...When the child cries or is unhappy, the mother reads this as meaning that she is a failure. This is why it is so important for a mother to know...that the process of growing up involves by definition things that her child is not going to like. Her job is not to create a bed of roses, but to help him learn how to pick his way through the thorns.”
    —Elaine Heffner (20th century)