GLOSSARY - Concepts of Database Management - page 370

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INTO clause The SQL clause that inserts values into
a table. An INTO clause consists of the word INTO
followed by the name of the table to be created.
Intranet An internal company network that uses
software tools typically used on the Internet and the
World Wide Web.
Join In relational algebra , the operation in which two
tables are connected on the basis of common data.
Join column The column on which two tables are
joined. Also see join .
Join line In an Access query, the line drawn between
tables to indicate how they are related.
Journal A file that contains a record of all the
updates made to a database; also called a log . The
DBMS uses the journal to recover a database that has
been damaged or destroyed.
Journaling Maintaining a journal or log of all
updates to a database.
Key The field on which data will be sorted; also
called a sort key .
LAN See local area network .
Legal-values integrity The property that no record
can exist in the database with a value in a field other
than a legal value.
Live system See production system .
Local area network (LAN) A configuration of several
computers connected together that allows users to
share a variety of hardware and software resources.
Local deadlock In a distributed database, deadlock
that occurs at a single site.
Local site From a user's perspective, the site in a
distributed system at which the user is working.
Location transparency The property that users do
not need to be aware of the location of data in a dis-
tributed database.
Locking A DBMS's denial of access by other users to
data while the DBMS processes one user's updates to
the database.
Log A file that contains a record of all the updates
made to a database; also called a journal . The DBMS
uses the log to recover a database that has been dam-
aged or destroyed.
Logical key A primary key that consists of a column
or collection of columns that is an inherent character-
istic of the entity.
Major sort key

Make-table query An Access query that creates a
table containing the results of a query.
Mandatory role The role in a relationship played by
an entity with a minimum cardinality of 1 (that is,
there must be at least one occurrence of the entity).
Many-to-many relationship A relationship between
two entities in which each occurrence of each entity can
be related to many occurrences of the other entity.
Many-to-many-to-many relationship A relationship
between three entities in which each occurrence of
each entity can be related to many occurrences of
each of the other entities.
Markup language A document language that con-
tains tags that describe a document's content and
appearance.
Message A request to execute a method. Also, data,
requests, or responses sent from one computer to
another computer on a network.
Metadata Data about the data in a database.
Metalanguage A language used to define another
language.
Method An action defined for a object class.
Minor sort key See secondary sort key .
Multidependent In a table with columns A, B, and C,
B is multidependent on A if each value for A is associ-
ated with a specific collection of values for B and, fur-
ther, this collection is independent of any values for C.
Multidetermine In a table with columns A, B, and C,
A multidetermines B if each value for A is associated
with a specific collection of values for B and, further,
this collection is independent of any values for C.
Multidimensional database The perceived structure
by users of the data in a data warehouse.
Multiple-column index See multiple-field index .
Multiple-field index An index built on more than
one field (column).
Multiplicity In UML, the number of objects that can
be related to an individual object on the other side of
a relationship; also called cardinality .
Multivalued dependence In a table with columns A,
B, and C, there is a multivalued dependence of col-
umn B on column A (also read as “B is multidepen-
dent on A” or “A multidetermines B”), if each value
for A is associated with a specific collection of values
for B and, furthermore, this collection is independent
of any values for C.
Natural join The most common form of a join.

See primary sort key .