Database Reference
In-Depth Information
Data
Text and numeric data
: Data fields comprising rows of information con-
taining discrete values related to some business entity. Most opera-
tional databases are almost completely text and numeric data fields.
Because there are discrete values, these can be individually retrieved,
queried, and manipulated to support some activity, reporting need,
or analysis.
Images
: Scanned pictures of documents, photos, and other multidimen-
sional forms can be stored in databases. The scanned image is a sin-
gle data field and is retrieved and updated as a single fact. Software
outside of the DBMS is used to manipulate the image.
Geographic data
: Geographic data is information about features on the
surface and subsurface of the Earth, including their location, shape,
description, and condition. Geographic information includes spatial
and descriptive tabular information in tabular and raster (image)
formats. A geographic information system (GIS) is a hardware and
software environment that captures, stores, analyzes, queries, and
displays geographic information. Geographic information is typi-
cally the basis for location-based decision making, land-use plan-
ning, emergency response, and mapping purposes.
Multimedia: voice, animation, and video
: Multimedia applications are
increasing as we employ new modalities of communicating with
users. Voice can be stored in a database to capture instructional,
informative messages that can then be played back rather than
displayed as text. This facilitates those situations where keyboards
and visual displays are difficult to utilize. Graphics, animation, and
video, likewise, offer an alternative way to inform users where simple
text does not communicate easily the complexity or the relationships
between informational components. An example might be graphic
displays of vessels and equipment allowing drill down to more
detailed information related to a part or component. Video may be
useful in demonstrating some complex operation as part of a train-
ing program.
Objects
: Objects are composites of other data types and other objects.
Unlike the relational model, objects form a hierarchy of information.
Objects contain facts about themselves and exhibit certain behav-
iors implemented as procedural code. They also inherit the facts and
behaviors of their parent objects up through the hierarchy. Relational
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