Database and Expert Systems Integration - Information Systems Reengineering, Integration and Normalization - page 313

* Credit Assessment Expert System in Crystal
* RULE LIST Thu Oct 21 22:13:33 1993 Page: 1
[ 1] bank references are good
IF DO: Test Expression customer_overdraft<50
AND DO: Test Expression customer_history$="good"
[ 2] credit rating
+ IF [ 4] customer status is house_owner
+ AND [ 3] customer salary is sufficient
+ AND [ 1] bank references are good
AND DO: Assign credit_rating$ = "good"
[ 3] customer salary is sufficient
IF DO: Test Expression monthly_salary>monthly_repayment
[ 4] customer status is house_owner
IF DO: Test Expression customer_status$="house-owner"
[ 5] CRYSTAL MASTER RULE
+IF [ 2] credit rating is good
[<Number>] means rule number
$ means the variable is text
Class Name: Credit
Attributes:
Customer_Status: Method(customer_status) /*output part*/
Monthly_Salary: Method(monthly_salary) /*output part*/
Monthly_Payment:Method(monthly_payment) /*output part*/
Customer_Overdraft:Method(customer_overdraft)/*output part*/
Customer_History: Method(customer_history) /*output part*/
Customer_Credit: Method(customer_credit) /*input part*/
Methods:
customer_status (): Text; {.........................}
monthly_salary (): Number; {.........................}
monthly_payment (): Number; {.........................}
customer_overdraft (): Number; {.........................}
customer_history (): Text;{.........................}
customer_credit (): Text;{.........................}
Fig. 8.4 An expert system and its coupling class in the frame model metadata
• Outputpartattributes:Allthedatathatarerequiredbytheexpertsystem.
• Inputpartattributes:Alltheresultsthataregeneratedbytheexpertsystem.
The conversion procedure will translate all input data variables that exist in the ex-
pert system into the output part attributes of the class. The program developer will
decide the variable name in which to save the resultant information from the expert
system. All the attributes of an expert system coupling class are represented as vir-
tual variables. The communication functions between the frame model metadata
and the external system are built into the method of each attribute. For example,
consider a credit assessment system called Credit that was built in the Crystal sys-
tem. The expert system and its coupling class are shown below in Crystal format
in Fig. 8.4 .