GLOSSARY - Concepts of Database Management - page 403

Identifying relationship A relationship that is necessary
for identification of an entity.
IIS (Internet Information Services) A Microsoft Web
server package that comes with many versions of its
operating systems.
Incomplete category In IDEF1X, a collection of
subtypes with the property that there are elements of
the supertype that are not elements of any subtype.
Independent entity An entity that does not require a
relationship to another entity for identification.
Index A file that relates key values to records that
contain those key values.
Index key The field or fields on which an index is built.
Information system The collection of data, people,
procedures, stored data, software, hardware, and infor-
mation required to support a specific set of related
functions.
Information-level design The step during database
design in which the goal is to create a clean, DBMS-
independent design that will support all user
requirements.
Inheritance The property that a subclass inherits the
structure of the class as well as its methods.
INSERT The SQL command to add new data to a table.
After the words INSERT INTO, you list the name of the
table, followed by the word VALUES. Then you list the
values for each of the columns in parentheses.
INTEGER The SQL data type for integer data.
Integrity A database has integrity if the data in it satis-
fies all established integrity constraints.
Integrity constraint A rule that must be followed by
data in a database.
Integrity rules See entity integrity, legal-values integ-
rity, and referential integrity.
Intelligent key A primary key that consists of a column
or collection of columns that is an inherent character-
istic of the entity.
Internet A worldwide collection of millions of intercon-
nected computers and computer networks that share
resources.
Internet Information Services (IIS) See IIS.
Interrelation constraint A constraint that involves more
than one relation.
INTERSECT The relational algebra command for
performing the intersection of two tables.
Intersection When comparing tables, an intersection is
a new table containing all rows that are in both original
tables.
Interview When determining system requirements,
a planned meeting during which you obtain system
requirements from other people.
INTO clause The SQL clause that inserts values into a
table. An INTO clause consists of the word INTO fol-
lowed by the name of the table to insert the values into.

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. The DBMS uses the journal to
recover a database that has been damaged or destroyed.
Also called a log.
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 distributed
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. The DBMS uses the log to recover a database
that has been damaged or destroyed. Also called a journal.
Logical key A primary key that consists of a column or
collection of columns that is an inherent characteristic
of the entity.
Major sort key See primary sort key.
Make-table query An Access query that creates a table
using 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.

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