Examples

One way to classify databases involves the type
of their contents, for example: bibliographic ,
document-text, statistical, or multimedia
objects. Another way is by their application
area, for example: accounting, music
compositions, movies, banking, manufacturing,
or insurance. A third way is by some technical
aspect, such as the database structure or
interface type. This section lists a few of the
adjectives used to characterize different kinds of
databases.
An in-memory database is a database that
primarily resides in main memory, but is
typically backed-up by non-volatile computer
data storage. Main memory databases are faster
than disk databases, and so are often used
where response time is critical, such as in
telecommunications network equipment.
[21] SAP HANA platform is a very hot topic for
in-memory database. By May 2012, HANA was
able to run on servers with 100TB main
memory powered by IBM. The co founder of the
company claimed that the system was big
enough to run the 8 largest SAP customers.
An active database includes an event-driven
architecture which can respond to conditions
both inside and outside the database. Possible
uses include security monitoring, alerting,
statistics gathering and authorization. Many
databases provide active database features in
the form of database triggers .
A cloud database relies on cloud technology.
Both the database and most of its DBMS reside
remotely, "in the cloud", while its applications
are both developed by programmers and later
maintained and utilized by (application's) end-
users through a web browser and Open APIs .
Data warehouses archive data from
operational databases and often from external
sources such as market research firms. The
warehouse becomes the central source of data
for use by managers and other end-users who
may not have access to operational data. For
example, sales data might be aggregated to
weekly totals and converted from internal
product codes to use UPCs so that they can be
compared with ACNielsen data. Some basic and
essential components of data warehousing
include retrieving, analyzing, and mining data,
transforming, loading and managing data so as
to make them available for further use.
A deductive database combines logic
programming with a relational database, for
example by using the Datalog language.
A distributed database is one in which both
the data and the DBMS span multiple
computers.
A document-oriented database is designed
for storing, retrieving, and managing document-
oriented, or semi structured data, information.
Document-oriented databases are one of the
main categories of NoSQL databases.
An embedded database system is a DBMS
which is tightly integrated with an application
software that requires access to stored data in
such a way that the DBMS is hidden from the
application’s end-users and requires little or no
ongoing maintenance. [22]
End-user databases consist of data
developed by individual end-users. Examples of
these are collections of documents,
spreadsheets, presentations, multimedia, and
other files. Several products exist to support
such databases. Some of them are much
simpler than full fledged DBMSs, with more
elementary DBMS functionality.
A federated database system comprises
several distinct databases, each with its own
DBMS. It is handled as a single database by a
federated database management system
(FDBMS), which transparently integrates
multiple autonomous DBMSs, possibly of
different types (in which case it would also be a
heterogeneous database system ), and provides
them with an integrated conceptual view.
Sometimes the term multi-database is used
as a synonym to federated database, though it
may refer to a less integrated (e.g., without an
FDBMS and a managed integrated schema)
group of databases that cooperate in a single
application. In this case typically middleware is
used for distribution, which typically includes an
atomic commit protocol (ACP), e.g., the two-
phase commit protocol, to allow distributed
(global) transactions across the participating
databases.
A graph database is a kind of NoSQL
database that uses graph structures with nodes,
edges, and properties to represent and store
information. General graph databases that can
store any graph are distinct from specialized
graph databases such as triplestores and
network databases.
In a hypertext or hypermedia database, any
word or a piece of text representing an object,
e.g., another piece of text, an article, a picture,
or a film, can be hyperlinked to that object.
Hypertext databases are particularly useful for
organizing large amounts of disparate
information. For example, they are useful for
organizing online encyclopedias , where users
can conveniently jump around the text. The
World Wide Web is thus a large distributed
hypertext database.
A knowledge base (abbreviated KB, kb or Δ
[23][24] ) is a special kind of database for
knowledge management , providing the means
for the computerized collection, organization,
and retrieval of knowledge . Also a collection of
data representing problems with their solutions
and related experiences.
A mobile database can be carried on or
synchronized from a mobile computing device.
Operational databases store detailed data
about the operations of an organization. They
typically process relatively high volumes of
updates using transactions . Examples include
customer databases that record contact, credit,
and demographic information about a business'
customers, personnel databases that hold
information such as salary, benefits, skills data
about employees, enterprise resource planning
systems that record details about product
components, parts inventory, and financial
databases that keep track of the organization's
money, accounting and financial dealings.
A parallel database seeks to improve
performance through parallelization for tasks
such as loading data, building indexes and
evaluating queries.
The major parallel DBMS architectures
which are induced by the underlying
hardware architecture are:
Shared memory architecture, where
multiple processors share the main
memory space, as well as other data
storage.
Shared disk architecture , where each
processing unit (typically consisting of
multiple processors) has its own main
memory, but all units share the other
storage.
Shared nothing architecture, where
each processing unit has its own main
memory and other storage.
Probabilistic databases employ fuzzy logic to
draw inferences from imprecise data.
Real-time databases process transactions
fast enough for the result to come back and be
acted on right away.
A spatial database can store the data with
multidimensional features. The queries on such
data include location based queries, like "Where
is the closest hotel in my area?".
A temporal database has built-in time
aspects, for example a temporal data model and
a temporal version of SQL. More specifically the
temporal aspects usually include valid-time and
transaction-time.
A terminology-oriented database builds upon
an object-oriented database , often customized
for a specific field.
An unstructured data database is intended to
store in a manageable and protected way
diverse objects that do not fit naturally and
conveniently in common databases. It may
include email messages, documents, journals,
multimedia objects, etc. The name may be
misleading since some objects can be highly
structured. However, the entire possible object
collection does not fit into a predefined
structured framework. Most established DBMSs
now support unstructured data in various ways,
and new dedicated DBMSs are emerging