Foreign Key

foreign key
See Also: key
[database structures] An attribute or set of attributes in one table that match the primary key attributes in another table. Foreign keys and primary keys are used to join tables in a database.

Foreign keys are defined in the ANSI SQL Standard, through a FOREIGN KEY constraint., The syntax to add such a constraint to an existing table is defined in SQL:2003 as shown below.

Foreign Key In a relational database management system terms, the item or column of a data that is used to relate one file to another.

foreign keyOne or more table attributes that can uniquely identify a record in another table. A foreign key is the primary key of another table. Foreign key-primary key relationships define a relational join. See also relate.

Foreign key support for all storage engines will likely be released with MySQL 5.2 (although it has been present since version 3.23.44 for InnoDB).
The current MySQL 5.1 development release is 5.1.22 RC.

foreign key p. 97 item in a relational table that contains a value identifying rows in another table; represents a relationship between two elements of a relational database. fuzzy set theory p.

For example, a table will not be given a foreign key value that does not exist as a primary key in another table. region A coverage feature class used to represent a spatial feature as one or more polygons.

table to a destination table, but the results are somewhat different. Spatial joins append the attributes of one layer to the attributes of another layer, based on the property of proximity or containment, rather than by typical primary-foreign key ...

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