Database and Expert Systems Integration - Information Systems Reengineering, Integration and Normalization - page 324

Table 8.4 The synonym table for the IHRMS
Attribute System-

Type

System-
Name

Synonym-
Degree

Attribute System-

Type

System-
Name

Person-id ES HRM Same ID DB Personnel

Name ES HRM Same Name DB Personnel

Person-
Directorate

ES HRM Same Directorate DB Personnel

Staff-Type ES HRM Same Staff-Type DB Personnel

Age ES HRM Same Age DB Personnel

Availability ES HRM Semantic Current-

Status

DB Personnel

Average-
Grade

ES HRM Semantic Average-

Mark

DB Personnel

Person-
Skill-1

ES HRM Same Skill-1 DB Personnel

Person-
Skill-2

ES HRM Same Skill-2 DB Personnel

or migration tools to reverse the database schema into a developer understandable
format. In the case study, the existing database is stored in a relational DBMS. We
used its data dictionary system to retrieve the database schema. The subschema of
personnel database can be seen in Table 8.2 .
The final phase of this step is to analyze the synonym relationship between these
attributes of the existing two systems. Table 8.4 shows the synonym of the attributes
for this case.
There are two kinds of synonym degree, i.e., Same and Semantic. “Same” means
that the two attributes represent the same object with the same semantic. “Seman-
tic” means that the two attributes use different semantics to represent the same ob-
ject. In this case, the developer must solve the semantic conflict problem between
these two attributes. For example, Availability of HRM indicates whether an em-
ployee is available for the new vacancy job or not. The values for this attribute are
“yes” or “no”. Current-Status of personnel database represents the job title for an
employee. If the employee does not have any duty, its values will be “Vacancy”. In
order to make the synonym relationship between these two attributes, the following
rule must be created.

IF Current-Status = “Vacancy”
THEN Availability = “yes”
ELSE Availability =”no”

The same problem will happen in the attributes of Average-Grade and Average-
Mark for this case study. The following shows another semantic rule for this prob-
lem.