We have a change history logging table named ‘ChangeHistory’ and would like several tables to have a to-many relationship to it.  

 

Student table has a to-many relationship to ChangeHistory named ‘toStudentChangeHistory’

 

School table has a to-many relationship to ChangeHistory named ‘toSchoolChangeHistory’

 

ChangeHistory includes an attribute named ‘foreignKeyId’ that will contain the primary key of the table that points to it; ie studentId or schoolId.  Thought I would also have a ChangeHistory attribute named ‘changeHistoryType’ that would distinguish the tables (value either ‘STUDENT’ or ‘SCHOOL’)

 

toStudentChangeHistory  join would be:

   Where Student.studentId = ChangeHistory.foreignKeyId   and  ChangeHistory.changeHistoryType = ‘STUDENT’

 

toSchoolChangeHistory  join would be:

   Where School.schoolId = ChangeHistory.foreignKeyId   and  ChangeHistory.changeHistoryType = ‘SCHOOL’

 

I can not figure out how to specify the changeHistoryType part of the join in the EOModeler.

 

Thought of a few work-a-rounds, but would rather not add additional attributes.  For instance, could add the changeHistoryType to both the Student and School tables.  Just seems like there should be a better way of doing this.

 

Thanks for your help.

 

JohnR

 

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