Automap multiple databases with Flask-SQLAlchemy - sqlalchemy

Question

I have an app currently working fine Automapping one database, but I need to access another database now as well. I tried to follow the Flask-SQLAlchemy documentation here: http://flask-sqlalchemy.pocoo.org/2.1/binds/, but it doesn't seem to work with the automap_base.
The only changes I made were creating SQLALCHEMY_BINDS and adding the __bind_key__ in models.py. The error I get is
sqlalchemy.exc.ArgumentError: Mapper Mapper|Table2|table2 could not assemble any primary key columns for mapped table 'table2'
However, both tables have a primary key column, and if I get rid of SQLALCHEMY_BINDS, set the URI to that of db2, and only have table2 in models.py, everything works fine.
I'm clearly doing something wrong, but I have no idea what it is. It looks like Flask is still looking for table2 in db1. I think my problem is that some change needs to be made to __init__.py as well, but I don't know what that would be.
config.py
SQLALCHEMY_DATABASE_URI = 'mysql://user#host/db1'
SQLALCHEMY_BINDS = {
'otherDB': 'mysql://user#host/db2',
}
__init__.py
from flask import Flask
from flask_sqlalchemy import SQLAlchemy
from sqlalchemy.ext.automap import automap_base
app = Flask(__name__)
app.config.from_object('config')
db = SQLAlchemy(app)
db.Model = automap_base(db.Model)
from app import models
db.Model.prepare(db.engine, reflect=True)
models.py
class Table1(db.Model):
__tablename__ = 'table1'
class Table2(db.Model):
__bind_key__ = 'otherDB'
__tablename__ = 'table2'

Answer 1

Automap is a extension of sqlalchemy to reflect an existing database into a new model. It has not been baked into flask-sqlalchemy. Plz see the issue here. You can connect to multiple databases with Flask-SQLAlchemy like this:
__init__.py
from flask import Flask
from flask_sqlalchemy import SQLAlchemy
app = Flask(__name__)
app.config.from_object('config')
db = SQLAlchemy(app)
from app import models
if __name__ == "__main__":
# show the table schema
print m3.Table1.__table__.c
print m3.Table2.__table__.c
models.py
db.reflect() # reflection to get table meta
class Table1(db.Model):
__tablename__ = 'table1'
class Table2(db.Model):
__tablename__ = 'table2'
__bind_key__ = 'otherDB'