sqlalchemy.exc.CircularDependencyError: Circular dependency detected

Question

The business logic - One Category may have multiple (1:M) attributes, like Category \"Memory\" could have attributes Speed, Size, Type etc.

at the same time one Cat

Answer 1

Okay found the answer - use post_update in relationship http://docs.sqlalchemy.org/en/latest/orm/relationship_persistence.html#post-update

so what I did is inside Category class is changed this:

SortByAttribute = relationship(
    "Attribute",
    uselist=False,
    foreign_keys=[sortByAttribute],
    primaryjoin="Attribute.ID==Category.sortByAttribute"
)

to this:

SortByAttribute = relationship(
    "Attribute",
    uselist=False,
    foreign_keys=[sortByAttribute],
    primaryjoin="Attribute.ID==Category.sortByAttribute",
    post_update=True
)