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:
“They have thrown away her electric toothbrush, someone else slips
The key into the lock of her safety-deposit box
At the Crocker-Anglo Bank; her seat at the cricket matches
Is warmed by buttocks less delectable than hers.”
—Randall Jarrell (1914–1965)
“Mine was, as it were, the connecting link between wild and cultivated fields; as some states are civilized, and others half-civilized, and others savage or barbarous, so my field was, though not in a bad sense, a half-cultivated field. They were beans cheerfully returning to their wild and primitive state that I cultivated, and my hoe played the Ranz des Vaches for them.”
—Henry David Thoreau (1817–1862)