Oops - should have asked the Flask-SQLAlchemy folks!
Thanks
On Tue, Oct 13, 2015 at 11:30 AM, Mike Bayer <mike...@zzzcomputing.com>
wrote:
>
>
> On 10/13/15 7:16 AM, Don O'Hara wrote:
> > I'm looking for advice on best SA coding practices to accomplish:
> >
> > 1. Use bind keys
>
> I'm not familiar with that, I see you using something called
> __bind_key__ and SQLALCHEMY_BINDS. These are not constructs that are
> part of SQLAlchemy; if this is a third-party package of some kind, I'd
> ask them for help.
>
>
>
>
>
> > 2. Add user-defined tags to tables, to allow iterating through the
> > metadata later to find tables with those tags.
> > 3. Use base table classes for common attributes and methods
> >
> > Is there a chance that class member names will get mangled in derived
> > classes,
> > and cause problems somewhere downstream? The code works now, but when I
> > remove one of the
> > base classes, and code the metadata directly in the table class things
> > break.
> >
> > I'd like to get a better understanding of how it all fits, and make
> > sure I'm setting things up correctly.
> >
> > Thanks,
> > Don
> >
> >
> >
> > My code:
> >
> > |
> > _inconfig.__py
> > _
> > SQLALCHEMY_BINDS ={
> > 'api':'postgresql+psycopg2://oharad:dino@localhost:5432/dev_api_02',
> >
> > 'person_indexes':'postgresql+psycopg2://oharad:dino@localhost
> :5432/dev_person_ix_01',
> >
> > 'analysis_result':'postgresql+psycopg2://oharad:dino@localhost
> :5432/dev_analysis_res_01'
> > }
> >
> > _in models/__init__.py_
> >
> > ACCOUNT_SCHEMA_NAMESPACE = 'account'
> >
> > class BaseAppTable(db.Model):
> > __abstract__ = True
> > def to_json(self):
> > json = {c.name: str(getattr(self, c.name)) or '' for c in
> > self.__table__.columns}
> > return json
> >
> >
> > _in models/account.py_
> >
> >
> > from models import BaseAppTable, db, ACCOUNT_SCHEMA_NAMESPACE
> >
> > _BASE_TABLE_ARGS = {'info': {'table_namespace':
> ACCOUNT_SCHEMA_NAMESPACE}}
> >
> > class BaseAccountTable(object):
> > __bind_key__ = 'api'
> > __table_args__ = _BASE_TABLE_ARGS
> >
> > class Account(BaseAppTable, BaseAccountTable):
> > __tablename__ = "account"
> > #
> > # need to explicitly code __table_args__ here to use 'tuple, dict'
> > syntax
> > __table_args__ = (UniqueConstraint('name', 'company_id',
> > name='account_uq_ix1'),
> > _BASE_TABLE_ARGS)
> > account_id = db.Column(db.Integer, primary_key=True)
> > name = db.Column(db.String(length=50), nullable=False)
> > company_id = db.Column(db.Integer,
> > db.ForeignKey('global.company.company_id'), nullable=False)
> >
> >
> > class RoleGroup(BaseAppTable, BaseAccountTable):
> > __tablename__ = "role_group"
> > role_group_id = db.Column(UUID, primary_key=True)
> > type_code = db.Column(db.SmallInteger, nullable=False)
> > name = db.Column(db.String(length=100), nullable=False, unique=True)
> >
> > |
> >
> > This code works fine, but I'm worried something might break due to name
> > mangling.
> >
> > When I change the code to avoid base classes, I get an error:
> >
> > |
> > classAccountCodeNamespace(BaseAppTable):
> > __tablename__ ="account_code_namespace"
> > __table_args__ =_BASE_TABLE_ARGS
> > __bind_key__ ='api'
> >
> > |
> >
> >
> > * # AssertionError: Bind 'api' is not specified. Set it in the
> > SQLALCHEMY_BINDS configuration variable*
> >
> >
> >
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