python 2.7 - Querying many-to-many in SQL Alchemy -

i have 2 two tables related third relationship table. basically, have many fits, can use number of tags, , i'm trying query fits tagged tag using tagid.

tag.py:

tags_table = table("tags", saveddata_meta,                             column("tagid", integer, primary_key = true),                             column("name", string, nullable = false, unique=true))  mapper(tag, tags_table) 

fit.py (stripped down)

fits_table = table("fits", saveddata_meta,                          column("id", integer, primary_key = true),                          column("ownerid", foreignkey("users.id"), nullable = true, index = true),                          column("name", string, nullable = false),                          column("timestamp", integer, nullable = false))  fit_tags = table("fit_tags", saveddata_meta,                             column("fitid", integer, foreignkey("fits.id"), primary_key = true),                             column("tagid", integer, foreignkey("tags.tagid"), primary_key = true))  mapper(fit, fits_table,        properties = {                      "_fit__tags" : relation(tag, secondary=fit_tags, backref="fits"),                      }) 

and here's function trying use:

def getfitswithtag(tagid, ownerid=none, where=none, eager=none):     """     fits tag tagid     if no user passed, users.     """     if isinstance(tagid, int):         if ownerid not none , not isinstance(ownerid, int):             raise typeerror("ownerid must integer")          filter = tag.tagid == tagid          if ownerid not none:             filter = and_(filter, fit.ownerid == ownerid)          filter = processwhere(filter, where)         eager = processeager(eager)         sd_lock:             fits = saveddata_session.query(fit).options(*eager).filter(filter).all()     else:         raise typeerror("tagid must integer")     return fits 

i can access tags of fit via fit._tags. however, not sure how query fits based on tag. i've tried many values filter i've come across while trying figure out.

add following line query:

def getfitswithtag(tagid, ownerid=none, where=none, eager=none):     # ...     fits = (saveddata_session.query(fit)             .join(fit_tags).filter(fit_tags.c.tagid == tagid) # @note: add me             .options(*eager).filter(filter)             ).all()     # ...     return fits 

also, why such strange name (_fit__tags) relationship? guess coming django. since sqlalchemy not give special meanings in those, can name tags.