IBM DB2 Manual page 541

are embedded within an application and
are prepared during the execution of the
application.
deferred write
The process of asynchronously writing
changed data pages to disk.
degree of parallelism
The number of concurrently executed
operations that are initiated to process a
query.
delete hole
The location on which a cursor is
positioned when a row in a result table is
refetched and the row no longer exists on
the base table. See also update hole.
delete rule
The rule that tells DB2 what to do to a
dependent row when a parent row is
deleted. Delete rules include CASCADE,
RESTRICT, SET NULL, or NO ACTION.
delete trigger
A trigger that is defined with the
triggering delete SQL operation.
delimited identifier
| A sequence of characters that are enclosed
within escape characters.
|
delimiter token
A string constant, a delimited identifier,
an operator symbol, or any of the special
characters that are shown in DB2 syntax
diagrams.
denormalization
The intentional duplication of columns in
multiple tables to increase data
redundancy. Denormalization is
sometimes necessary to minimize
performance problems. Contrast with
normalization.
dependent
An object (row, table, or table space) that
has at least one parent. The object is also
said to be a dependent (row, table, or
table space) of its parent. See also parent
row, parent table, and parent table space.
dependent row
A row that contains a foreign key that
matches the value of a primary key in the
parent row.
dependent table
A table that is a dependent in at least one
referential constraint.
descendent
An object that is a dependent of an object
or is the dependent of a descendent of an
object.
descendent row
A row that is dependent on another row,
or a row that is a descendent of a
dependent row.
descendent table
A table that is a dependent of another
table, or a table that is a descendent of a
dependent table.
deterministic function
A user-defined function whose result is
dependent on the values of the input
arguments. That is, successive invocations
with the same input values produce the
same answer. Sometimes referred to as a
not-variant function. Contrast with
nondeterministic function (sometimes
called a variant function).
dimension
A data category such as time, products, or
markets. The elements of a dimension are
referred to as members. See also
dimension table.
dimension table
The representation of a dimension in a
star schema. Each row in a dimension
table represents all of the attributes for a
particular member of the dimension. See
also dimension, star schema, and star join.
directory
The DB2 system database that contains
internal objects such as database
descriptors and skeleton cursor tables.
disk A direct-access storage device that records
data magnetically.
distinct type
A user-defined data type that is
represented as an existing type (its source
type), but is considered to be a separate
and incompatible type for semantic
purposes.
distributed data
Data that resides on a DBMS other than
the local system.
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Glossary