| slovo | definícia |
database management system
(encz) | database management system, n: |
database management system
(wn) | database management system
n 1: a software system that facilitates the creation and
maintenance and use of an electronic database [syn:
database management system, DBMS] |
database management system
(foldoc) | database management system
DBMS
(DBMS) A suite of programs which typically manage
large structured sets of persistent data, offering ad hoc
query facilities to many users. They are widely used in
business applications.
A database management system (DBMS) can be an extremely
complex set of software programs that controls the
organisation, storage and retrieval of data (fields, records
and files) in a database. It also controls the security and
integrity of the database. The DBMS accepts requests for data
from the application program and instructs the operating
system to transfer the appropriate data.
When a DBMS is used, information systems can be changed much
more easily as the organisation's information requirements
change. New categories of data can be added to the database
without disruption to the existing system.
Data security prevents unauthorised users from viewing or
updating the database. Using passwords, users are allowed
access to the entire database or subsets of the database,
called subschemas (pronounced "sub-skeema"). For example, an
employee database can contain all the data about an individual
employee, but one group of users may be authorised to view
only payroll data, while others are allowed access to only
work history and medical data.
The DBMS can maintain the integrity of the database by not
allowing more than one user to update the same record at the
same time. The DBMS can keep duplicate records out of the
database; for example, no two customers with the same customer
numbers (key fields) can be entered into the database.
Query languages and report writers allow users to
interactively interrogate the database and analyse its data.
If the DBMS provides a way to interactively enter and update
the database, as well as interrogate it, this capability
allows for managing personal databases. However, it may not
leave an audit trail of actions or provide the kinds of
controls necessary in a multi-user organisation. These
controls are only available when a set of application programs
are customised for each data entry and updating function.
A business information system is made up of subjects
(customers, employees, vendors, etc.) and activities (orders,
payments, purchases, etc.). Database design is the process of
deciding how to organize this data into record types and how
the record types will relate to each other. The DBMS should
mirror the organisation's data structure and process
transactions efficiently.
Organisations may use one kind of DBMS for daily transaction
processing and then move the detail onto another computer that
uses another DBMS better suited for random inquiries and
analysis. Overall systems design decisions are performed by
data administrators and systems analysts. Detailed database
design is performed by database administrators.
The three most common organisations are the {hierarchical
database}, network database and relational database. A
database management system may provide one, two or all three
methods. Inverted lists and other methods are also used. The
most suitable structure depends on the application and on the
transaction rate and the number of inquiries that will be
made.
Database machines are specially designed computers that hold
the actual databases and run only the DBMS and related
software. Connected to one or more mainframes via a
high-speed channel, database machines are used in large volume
transaction processing environments. Database machines have a
large number of DBMS functions built into the hardware and
also provide special techniques for accessing the disks
containing the databases, such as using multiple processors
concurrently for high-speed searches.
The world of information is made up of data, text, pictures
and voice. Many DBMSs manage text as well as data, but very
few manage both with equal proficiency. Throughout the 1990s,
as storage capacities continue to increase, DBMSs will begin
to integrate all forms of information. Eventually, it will be
common for a database to handle data, text, graphics, voice
and video with the same ease as today's systems handle data.
See also: intelligent database.
(1998-10-07)
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| | podobné slovo | definícia |
object-oriented database management system
(encz) | object-oriented database management system,řídící systém objektově
orientované databáze n: [it.] Petr Menšík |
relational database management system
(encz) | relational database management system, n: |
object-oriented database management system
(wn) | object-oriented database management system
n 1: a database management system designed to manage an object-
oriented database |
relational database management system
(wn) | relational database management system
n 1: a database management system designed to manage a
relational database |
dynamic database management system
(foldoc) | dynamic database management system
dynamic DBMS
(dynamic DBMS) A database with "value-based"
relationships where typically the relationship is specified at
retrieval time and the locations of related records are
discovered during retrieval. Both Independent Logical File
(ILF) databases and relational databases are value-based.
The opposite is a static database management system.
(1998-10-07)
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integrated database management system
(foldoc) | Integrated Database Management System
(IDMS) A network DBMS written by the staff of
B.F.Goorich (Akron, Ohio, USA) circa 1972 and sold to
Cullinet (Originally Cullinane, now part of {Computer
Associates}).
IDMS was licensed to ICL in 1976 for porting to, and
subsequent development on, their computers. It was
implemented on the ICL 1900 Series (DME George 2,
George 3, CME, TME), System 4, and ICL 2900 Series
(later Series 39 Corporate Servers). The latest version runs
on Series 39 OpenVME as IDMSX (IDMS extended).
[Was it a relational database?]
(1995-04-19)
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relational database management system
(foldoc) | relational database
RDBMS
relational database management system
relational DBMS
(RDBMS - relational database management system) A
database based on the relational model developed by
E.F. Codd. A relational database allows the definition of
data structures, storage and retrieval operations and
integrity constraints. In such a database the data and
relations between them are organised in tables. A table is
a collection of rows or records and each row in a table
contains the same fields. Certain fields may be designated
as keys, which means that searches for specific values of
that field will use indexing to speed them up.
Where fields in two different tables take values from the same
set, a join operation can be performed to select related
records in the two tables by matching values in those fields.
Often, but not always, the fields will have the same name in
both tables. For example, an "orders" table might contain
(customer_id, product_code) pairs and a "products" table might
contain (product_code, price) pairs so to calculate a given
customer's bill you would sum the prices of all products
ordered by that customer by joining on the product-code fields
of the two tables. This can be extended to joining multiple
tables on multiple fields. Because these relationships are
only specified at retreival time, relational databases are
classed as dynamic database management system.
The first commercial RDBMS was the {Multics Relational Data
Store}, first sold in 1978.
INGRES, Oracle, Sybase, Inc., Microsoft Access, and
Microsoft SQL Server are well-known database products and
companies. Others include PostgreSQL, SQL/DS, and RDB.
["Managing Data Bases, Four Critical Factors" Michael
M. Gorman, QED Information Sciences, Inc.].
["An Introduction To Database Systems" (6th ed) C. J. Date,
Addison Wesley (an excellent source of detailed info)].
["An End-User's Guide to Data Base" James Martin, Prentice
Hall (excellent place to begin learning about DBMS)].
(2002-06-10)
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static database management system
(foldoc) | static database management system
static DBMS
(static DBMS) A database consisting of
"information-based relationships", one that is rigorously
structured to facilitate retrieval and update in terms of
inherent relationships. This creates a static environment
wherein the locations of the related records are already
known. Typical static DBMS are either hierarchical (IMS,
System 2000) or a CODACYL (network or plex) DBMS (such as
TOTAL, IDMS, IDS, DMS-2). These environments
facilitate rapid, high volume processing of data.
The opposite is a dynamic database management system.
(1998-10-07)
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