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Glossary

F

fan-out replication
A replication model in which data from one source table is copied to multiple target tables, thereby distributing the data to multiple locations. Contrast with consolidation replication.

fast communication manager (FCM)
A group of functions that provide internodal communication support.

fenced
A type of user-defined function or stored procedure that is defined to protect the DBMS from modifications by the function. The DBMS is isolated from the function or stored procedure by a barrier. Contrast with not-fenced.

file reference variable
A host variable that is used to indicate that data resides in a file on the client rather than in a client memory buffer.

file server
A workstation that runs the NetWare** operating system software and acts as a network server. DB2 uses the file server to store DB2 server address information, which a DB2 client retrieves to establish an IPX**/SPX client-server connection.

filter
A device or program that separates data, signals, or material in accordance with specified criteria. (A)

First Failure Service Log
A file (db2diag.log) that contains diagnostic messages, diagnostic data, alert information, and related dump information. This file is used by database administrators.

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

flagger
A precompiler option that identifies SQL statements in applications that do not conform to selected validation criteria (for example, the ISO/ANSI SQL92 Entry level standard).

foreign key
A key that is part of the definition of a referential constraint and that consists of one or more columns of a dependent table.

foreign update
An update that was applied to a target table and replicated to the local table.

forward recovery
A process used to roll forward a database or table space. It allows a restored database or table space to be rebuilt to a specified point in time by applying the changes recorded in the database log.

fullselect
A subselect, a values-clause, or a number of both that are combined by set operators.

fully qualified LU name
See network-qualified name.

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

function body
The piece of code that implements a function.

function family
A set of functions with the same function name. The context determines whether the usage refers to a set of functions within a particular schema, or all the relevant functions with the same name within the current function path.

function invocation
The use of a function together with any argument values being passed to the function body. The function is invoked by its name.

function path
An ordered list of schema names that restricts the search scope for unqualified function invocations and provides a final arbiter for the function selection process.

function path family
All the functions of the given name in all the schemas identified (or used by default) in the user's function path.

function resolution
The process, internal to the DBMS, for which a particular function instance is selected for invocation. The function name, the data types of the arguments, and the function path are used to make the selection. Synonymous with function selection.

function selection
Synonym for function resolution.

function shipping
The shipping of the subsections of a request to the specific node that contains the applicable data.

function signature
The logical concatenation of a fully qualified function name with the data types of all of its parameters. Each function in a schema must have a unique signature.


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