Database Reference
In-Depth Information
2.5.4 Application Development Subsystem
The
application development subsystem
(ADS or its equivalent) contains tools for
developing application components such as forms, reports, and menus. In some cases,
it may be merged with the user interface subsystem. Typically, this subsystem provides a
graphical user interface (GUI), which is superimposed on an underlying host language.
The suite may include an automatic code generator (as in Delphi and Team Developer),
or seamless access of the compiler of the host language (as in Oracle).
Other facilities that may be included such as:
•
Report writer
•
Project manager
•
Menu builder
•
Graphic data interpreter
2.5.5 Data Administration Subsystem
The
data administration subsystem
(DAS) consists of a collection of utilities that facilitate
effective management of the database. Included in this subsystem are facilities for backup
and recovery, database tuning, and storage management. It is typically used by DBAs as
well as software engineers.
2.5.6 Data Dictionary Subsystem
Also called the
system catalog
in many systems, the
data dictionary
(DD) contains
information on the database structure as well relationships among database objects. It is
automatically created and maintained by the DBMS.
The system catalog contains all metadata for the database. It can be queried using
the same commands used to manipulate source data; it is therefore of inestimable value
to the DBAs and software engineers. More will be said about the system catalog later in
the course.
