Английский для пользователей компьютеров. Ч.2. Белобородова М.Л - 27 стр.

business users' perspective, involves defining user information needs;
analyzing data element requirements and logical groupings; finalizing the
design; and creating the data dictionary. During the logical design the schema
(the organization of the entire database, including the structure type) and the
subschema (the way certain data elements are linked) are defined.
   The physical design involves how the data will be physically arranged and
stored on the storage devices used by the DBMS. During this design phase the
database is actually set up, and the data is stored.
Databases are important business resources, and DBMS software is
sophisticated;
both of them must be carefully operated and controlled. For this purpose, the
job of database administrator (DBA) has been created. The main
responsibilities of a database administrator are (1) guiding database design; (2)
overseeing database implementation and operation; (3) user coordination; (4)
backup and recovery; (5) performance monitoring; and (6) system security.
   In general, the main advantages of database managment systems are (1)
elimination of data redundancy; (2) increased ease of file updating; (3)
increased data independence and simplification of program and maintenance;
(4) increased user productivity and efficiency; (5) increased security; and (6)
standardization of data definitions.
   The main disadvantages are (1) complexity; (2) high cost of
implementation; and (3) vulnerability of consolidated business data in a central
database.

BE   SURE THAT YOU UNDERSTAND THE MEANING OF THE KEY
TERMS:
child record
database
database administrator(DBA)
database management system(DBMS)
data dictionary
data redundancy
logical database
network database model
one-to-many relationship
parent record
physical database design
program independence
relational database model
root record
(sub)schema