This documentation uses several terms that must be clarified
for a good understanding.
- Product
- The Product defines all software components that compose
the information system managing a given domain. Usually, the domains
covered by programs written in BDL are business oriented.
- End User
- The End User is the person that uses the Product; that
person works on hardware called the Workstation.
- Programs
- The Programs are the software components that are developed
and distributed by the supplier of the Product. Programs typically
implement business rules and processing, usually called Business Logic.Programs are
executed by the Runtime
System on the Application Server machine. These components
are typically p-code modules, forms and additional files.
- Developer
- The Developer is the person in charge of the conception
and implementation of the Product components.
- Application Data
- Application Data defines the data manipulated by the Product. It is typically managed
by one or more Database
Systems. The Application Data has a volatile state when
loaded in the Runtime
System, and it has a static state when stored in the Database
System.
- Database
- The Database is a logical entity regrouping the Application Data. It
is managed by the Database
System.
- Database System
- The Database System is the software that manages data storage
and searching; it is usually installed on the Database Server machine
and is supported by a tier software vendor. It is the software managing
the Data in the Three-Tier C/S model.
- Development Database
- The Development Database is the Database used in the application
development environment.
- Production Database
- The Production Database is the Database used on production
sites.
- Front End
- The Front End is the software that manages the display
of the User Interface on
the Workstation machine.
This component is historically called "The Client", in a thin Client/Server
context. It is the software managing the Presentation in the Three-Tier
C/S model.
- Runtime System
- The Runtime System is the software that manages the execution
of the Programs, where
the Business Logic is processed. It is typically implemented by the Dynamic
Virtual Machine (DVM) and historically called "The Runner". It
is the software managing the Processing in the Three-Tier C/S model.
- User Interface
- The User Interface defines the parts of the Programs that
interact with the end user, including interactive elements like windows,
screens, input fields, buttons and menus. It is displayed on the Workstation. This can typically
be implemented by different kinds of Front Ends, based on ASCII
terminals, graphical platforms (Microsoft™ Windows™, X11) or even through
web protocols like HTML over HTTP.
- Workstation
- The Workstation identifies the hardware used by the End User to interact with the Product. It can be an ASCII
Terminal, a PC, a diskless station or even a cellular phone, as long
as a Front End is available
on that hardware.