FW: Entity Modeller == EOModeler?- vertical inheritance(solved?)
FW: Entity Modeller == EOModeler?- vertical inheritance(solved?)
- Subject: FW: Entity Modeller == EOModeler?- vertical inheritance(solved?)
- From: "Ren, Kevin" <email@hidden>
- Date: Mon, 23 Jun 2008 12:25:28 +1200
- Thread-topic: Entity Modeller == EOModeler?- vertical inheritance(solved?)
Title: FW: Entity Modeller == EOModeler?- vertical inheritance(solved?)
Sorry, failed. Only can delete.
I remembered it's succeed. Maybe I did too much change, so forgot make clean build.
I gave up,
"Vertical is the least efficient and the least used hence has a higher probability of bugs."
Thanks
Kevin
______________________________________________
From: Ren, Kevin
Sent: Monday, 23 June 2008 12:03 p.m.
To: 'email@hidden'
Subject: Entity Modeller == EOModeler?- vertical inheritance(solved?)
Hi,
Problem solved for this, but not sure for all "vertical inheritance".
What I done
1. ALTER TABLE EMPLOYEE ADD CONSTRAINT EMPLOYEE_ADDRESS_FK FOREIGN KEY (ADDRESS_ID) REFERENCES ADDRESS (ADDRESS_ID);
2. ALTER TABLE WORK_ADDRESS ADD CONSTRAINT WORK_ADDRESS_ADDRESS_FK FOREIGN KEY (ADDRESS_ID) REFERENCES ADDRESS (ADDRESS_ID);
After this I can insert and delete Teacher with workAddress.
Maybe just one scenario for "vertical inheritance", because I found in the list:
Chuck's comment of "Vertical is the least efficient and the least used hence has a higher probability of bugs."
Hopeful that's all "vertical inheritance".
Thanks
Kevin
My question is coming from "SQL generation" in Entity Modeler.
When I am playing the code with Apple/example/SophisticatedDatabaseExample.
Copied from README:
The SophisticatedDatabaseExample demonstrates the use of inheritance, flattening, and multiple models.
The Person class is abstract. Student, Parent and Employee inherit from Person using horizontal inheritance.
The Admin,Staff, Teacher classes all inherit from Employee using single-table inheritance.
The HomeAddress, WorkAddress, and BillingAddress inherit from Address using vertical inheritance.
The relationship between Student and ScheduledCourse is an example of a many-to-many "flattened" relationship. The normal indirect "join" table values are extracted into each side of the relationship, giving the appearance of a direct many-to-many relationship between entities(classes). This relationship is interesting because Student is an entity in the School model but ScheduledClass is an entity in the Course model.
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