SQLAlchemy：filter_by 在外部属性上带有 like()

Question

I have the following models:

class CRRun(Base):
    ...
    crID = Column(u'CR_ID', INTEGER(), ForeignKey(CR.id), primary_key=True,
                  nullable=False)
    cr = relationship(CR, backref=backref("CR_RUN", uselist=False))
    ...

class CR(Base):
    ...
    id = Column(u'CR_ID', INTEGER(), primary_key=True, nullable=False)
    state = Column(u'STATE', VARCHAR(20))
    ...

I am then trying to do the following:

state = 'some value'
crsRuns = Session.query(CRRun)
crsRuns = crsRuns.options(eagerload('cr'))
                 .filter(CRRun.cr != None)
                 .filter(CRRun.cr.state.like('%' + state + '%'))

However, this causes the following error:

AttributeError: Neither 'InstrumentedAttribute' object nor 'Comparator' object has an attribute 'state'

How can I filter my query by the value of a column in a table that's connected to the table I'm querying via a foreign key?

Answer 1

Try:

state = 'some value'
crsRuns = Session.query(CRRun)
crsRuns = crsRuns.options(eagerload('cr')) \
    .filter(CRRun.cr.has(
        CR.state.like('%' + state + '%')
    ))

Answer 2

I ended up doing the following:

crsRuns = Session.query(CRRun, CR, Run).join(CR).join(Run)
crsRuns = crsRuns.filter(CR.state.like('%' + state + '%'))