F

federated database

The combination of a DB2 Universal Database server (in Linux, UNIX, and Windows environments) and multiple data sources to which the server sends queries. In a federated database system, a client application can use a single SQL statement to join data that is distributed across multiple database management systems and can view the data as if it were local.

fetch orientation

The specification of the desired placement of the cursor as part of a FETCH statement (for example, BEFORE, AFTER, NEXT, PRIOR, CURRENT, FIRST, LAST, ABSOLUTE, and RELATIVE).

fixed-length string

A character or graphic string whose length is specified and cannot be changed. Contrast with varying-length string.

foreign key

A column or set of columns in a dependent table of a constraint relationship. The key must have the same number of columns, with the same descriptions, as the primary key of the parent table. Each foreign key value must either match a parent key value in the related parent table or be null.

free space

The total amount of unused space in a page; that is, the space that is not used to store records or control information is free space.

full outer join

The result of a join operation that includes the matched rows of both tables that are being joined and preserves the unmatched rows of both tables.

See also [join]

fullselect

A subselect, a values-clause, or a number of both that are combined by set operators. Fullselect specifies a result table. If UNION is not used, the result of the fullselect is the result of the specified subselect.

function

A mapping, which is embodied as a program (the function body) that is invocable by means of zero or more input values (arguments) to a single value (the result).

Functions can be user-defined, built-in, or generated by DB2.

See also [column function]

See also [scalar function]

See also [built-in function]

See also [cast function]

See also [external function]

See also [sourced function]

See also [SQL function]

See also [user-defined function]

function package

A package that results from binding the DBRM for a function program.