SQLA: Multiple relationships to another model with search

If there’s more than one relationship to another model then (I believe) there’s no way to add them to search.

class A(Base):
    __tablename__ = 'a'
    id = sa.Column(sa.Integer, primary_key=True)
    name = sa.Column(sa.Text)


class B(Base):
    __tablename__ = 'b'
    a1_id = sa.Column(sa.Integer, sa.ForeignKey(A.id))
    a1 = orm.relationship(A.id, foreign_keys=[a1_id])
    a2_id = sa.Column(sa.Integer, sa.ForeignKey(A.id))
    a2 = orm.relationship(A.id, foreign_keys=[a2_id])

...

class BModelView(ModelView):
    ...
    column_searchable_list = (
        B.a1.name,
    )
# AttributeError: Neither 'InstrumentedAttribute' object nor 'Comparator' object associated with B.a1 has an attribute 'name'

class BModelView(ModelView):
    ...
    column_searchable_list = (
        B.a1,  # (or the string "a1")
    )
# Exception: Invalid field B.a1: does not contains any columns.


class BModelView(ModelView):
    ...
    column_searchable_list = (
       A.name,
    )
# sqlalchemy.exc.InvalidRequestError: Could not find a FROM clause to join from.  Tried joining to a, but got: Can't determine join between 'b' and 'a'; tables have more than one foreign key constraint relationship between them. Please specify the 'onclause' of this join explicitly.

How can we add support for this? Would be nice with an API like this:

class BModelView(ModelView):
    ...
    column_searchable_list = (
       # (local_relationship, foreign_attribute)
       (B.a1, A.name),
    )

[bepetersn]

I’m wondering if you’re seeing this work for filters. I get this error when trying to filter across multiple relationships:

File "/home/brian/.virtualenvs/my-project/src/flask-admin/flask_admin/contrib/sqla/tools.py", line 198, in is_hybrid_property
    attr = getattr(last_model, names[i])
AttributeError: 'Mapper' object has no attribute 'location'

I can open a new issue also if you want.

[mrjoes]

Try 'B.a1.name' as a string.