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:
“The word “forbearance” is the key to a happy home.”
—Chinese proverb.
“Vigil strange I kept on the field one night;
When you my son and my comrade dropt at my side that day,
One look I but gave which your dear eyes return’d with a look I
shall never forget,
One touch of your hand to mine O boy, reach’d up as you lay on the ground,”
—Walt Whitman (1819–1892)