A key field is a field or set of fields (a key is then said to be a composite key) of a database (typically a relational database) table which together form a unique identifier for a database record (a table entry). The aggregate of these fields is usually referred to simply as "the key". Key fields also define searches. Relational databases enforce referential integrity of their tables by matching primary keys with foreign keys. Keys can also be distinguished in technical keys (also known as surrogate keys) and business keys (also known as natural keys or domain keys).
Sometimes programmers embed a list of key values in a non-key character string fields. Many times the values in these fields cannot be guaranteed since no database can enforce the integrity of these values.
Also see primary key and foreign key.
Famous quotes containing the words key and/or field:
“I cannot tell what I am as much afraid of, as a woman who invariably washes on Monday. It is a kind of key to character; and if her mouth is not puckered and her brow wrinkled, they will be, unless she repents.”
—Jane Grey Swisshelm (1815–1884)
“Yet, hermit and stoic as he was, he was really fond of sympathy, and threw himself heartily and childlike into the company of young people whom he loved, and whom he delighted to entertain, as he only could, with the varied and endless anecdotes of his experiences by field and river: and he was always ready to lead a huckleberry-party or a search for chestnuts and grapes.”
—Ralph Waldo Emerson (1803–1882)