Database and Expert Systems Integration - Information Systems Reengineering, Integration and Normalization - page 325

IF Average-Mark >= 80
hTHEN Average-Grade = “high”
ELSE IF average-mark >= 50
THEN Average-Grade = “middle”
ELSE Average-Grade = “low”
Step 2. Create Coupling Classes
The frame model metadata will create two coupling classes for the IHRMS.
Figure 8.11 shows the HRM ES coupling class and Fig. 8.12 shows the Personnel
DB coupling class. The attributes of ES coupling class will come from the attributes
of HRM. The Variable style of HRM attributes will become to output part attributes
of the ES coupling class (see Table 8.3 ). The system developer must define an in-
put part attribute that will store the result of the HRM ES. In this case, the system
developer defines an attribute, called find-employee. The attached method of this
attribute will execute the external ES. The attribute of DB coupling class is a mirror
of personnel database schema (see Table 8.4 ). Each attribute within the coupling
class will contain a method.
The standard frame for the method will depend on the attribute that is an output
part attribute or input part attribute. Figure 8.13 shows the standard algorithm of
these two type methods.
There are four generic functions for the the frame model metadata to enable
process the coupling class.
• Request : The function is to get a value from the other class's attribute of the
system.
• Write : The function will write a value to the standard IO stream of the existing
external system or a special defined IO stream.
• Receive : The function will read a value from the standard IO stream of the exist-
ing external system or a special defined IO stream.
• Save : The function will save a value to the other class's attribute of the system.
For example, the method for the “Name” attribute of HRM coupling class will be
like:
HRM.name(): Te xt;
{
/* output part attribute variable */
Request (HRM.name);
Write(HRM.name, standard-IO-stream)
}