Hello John! Constaint name must be unique at schema level (in your case APP schema). In other words name for example first FK constaint as FK_PATIENT_PERSON_ID and second as FK_EMPLOYEE_PERSON_ID (FK_table_referencingColumn).
Hope that helps! Libor 2012/4/4 John Steele <[email protected]> > > I have three tables Person, Patient, and Employee. Both Patient and > Employee > have a Foreign Key to Person; however, when creating the constraint for the > second time I get the following error: > > Constraint 'PERSON_FK' already exists in Schema 'APP'. > > [code] > CREATE TABLE PERSON ( > PERSON_ID INTEGER NOT NULL GENERATED ALWAYS AS IDENTITY (START WITH > 1, > INCREMENT BY 1) > ); > > CREATE TABLE PATIENT ( > PATIENT_ID INTEGER NOT NULL GENERATED ALWAYS AS IDENTITY (START > WITH 1, > INCREMENT BY 1), > PERSON_ID INTEGER NOT NULL > ); > > ALTER TABLE PATIENT > ADD CONSTRAINT PERSON_FK Foreign Key ( > PERSON_ID) > REFERENCES PERSON ( > PERSON_ID); > > > CREATE TABLE EMPLOYEE ( > EMPLOYEE_ID INTEGER NOT NULL GENERATED ALWAYS AS IDENTITY (START > WITH 1, > INCREMENT BY 1), > PERSON_ID INTEGER NOT NULL > ); > > ALTER TABLE EMPLOYEE > ADD CONSTRAINT PERSON_FK Foreign Key ( > PERSON_ID) > REFERENCES PERSON ( > PERSON_ID); > [/code] > > What do you do in this situation? Do you only create on constraint and then > reference it when using it again? If so, how? > > Thanks, > John Steele > > -- > View this message in context: > http://old.nabble.com/Constraint-already-exists-in-Schema-%27APP%27-tp33564657p33564657.html > Sent from the Apache Derby Users mailing list archive at Nabble.com. > >
