sqlalchemy.exc.ProgrammingError: (ProgrammingError) there is no unique constraint matching given keys for referenced table

Question

I am using sqlalchemy to create two tables in the following:

class Classroom(Base): __tablename__ = 'classroom' building = Column(String(256), primary_key = True) room_no = Column(String(256), primary_key = True) capacity = Column(Integer) class Section(Base): __tablename__ = 'section' course_id = Column(String(256), ForeignKey('course.course_id'), primary_key = True) building = Column(String(256), ForeignKey('classroom.building')) room_no = Column(String(256), ForeignKey('classroom.room_no'))

However, I got the error saying:

 sqlalchemy.exc.ProgrammingError: (ProgrammingError) there is no unique constraint matching given keys for referenced table "classroom"

Craig Ringer · Accepted Answer · 2014-01-26 12:12:03Z

I just figured out, in this case I need to have a multicolumn foreig key constraints: Changed my section model to be:

class Section(Base): __tablename__ = 'section' course_id = Column(String(256), ForeignKey('course.course_id'), primary_key = True) building = Column(String(256)) room_no = Column(String(256)) __table_args__ = (ForeignKeyConstraint([building, room_no],[Classroom.building, Classroom.room_no]), {})

and everything works.

Thanks for following up when you figured it out, rather than just abandoning the question.

Collectives™ on Stack Overflow

sqlalchemy.exc.ProgrammingError: (ProgrammingError) there is no unique constraint matching given keys for referenced table

1 Answer 1

1 Comment

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

1 Comment

Related