Failed to change the "id" column into "_id"

Question

Failed to change the "id" column into "_id"

Opened this issue 12 years ago · 4 comments

Hello,

I tried to change the "id" column into "_id", but failed. The exception is as following:
sqlalchemy.exc.NoReferencedColumnError: Could not create ForeignKey 'users.id' on table 'posts': table 'users' has no column named 'id'

It seems there is other hard-coded in the library.

The code is as following:

# coding: utf-8
# test.py

# https://github.com/tylerlong/quick_orm
# pip install quick_orm
from quick_orm.core import MyDeclarativeMeta, Database, StringUtil, models
from sqlalchemy import Column, String, Text, Integer, DateTime

class myMeta(MyDeclarativeMeta):
    """metaclass for all model classes, let model class inherit Database.Base and handle table inheritance.
    All other model metaclasses are either directly or indirectly derived from this class.
    """
    def __new__(cls, name, bases, attrs):
        # add Database.Base as parent class
        bases = list(bases)
        if object in bases:
            bases.remove(object)
        bases.append(Database.Base)
        seen = set()
        bases = tuple(base for base in bases if not base in seen and not seen.add(base))

        attrs['__tablename__'] = StringUtil.camelcase_to_underscore(name)
        print attrs['__tablename__']
        attrs['_id'] = Column(Integer, primary_key = True)
        attrs['created_at'] = Column(DateTime)
        attrs['updated_at'] = Column(DateTime)
        attrs['_readable_name'] = attrs['__tablename__']
        attrs['_readable_names'] =  attrs['_readable_name'] + 's'
        attrs['_one_to_models'] = attrs['_many_to_models'] = []
        if not '__mapper_args__' in attrs:
            attrs['__mapper_args__'] = {}

        # the for loop bellow handles table inheritance
        for base in [base for base in bases if base in models]:
            if not hasattr(base, 'real_type'):
                base.real_type = Column('real_type', String(24), nullable = False, index = True)
                base.__mapper_args__['polymorphic_on'] = base.real_type
                base.__mapper_args__['polymorphic_identity'] = base._readable_name
            attrs['_id'] = Column(Integer, ForeignKey('{0}._id'.format(base._readable_name), ondelete = "CASCADE"), primary_key = True)
            attrs['__mapper_args__']['polymorphic_identity'] = attrs['_readable_name']
            attrs['__mapper_args__']['inherit_condition'] = attrs['_id'] == base._id

        return MyDeclarativeMeta.__new__(cls, name, bases, attrs)

__metaclass__ = myMeta

class Users :
    last_name = Column(String(50))
    lfirst_name = Column(String(50))

@Database.foreign_key(Users, ref_name='author', backref_name='posts') 
class Posts :
    title = Column(String(200))
    content = Column(Text)

Database.register()

if __name__ == '__main__':
    db = Database('mysql://root:root@127.0.0.1:3306/webscraping?charset=utf8')
    db.create_tables()

Thanks,
Qi

Answer 1 · 2013-02-22T08:52:56.000Z

Yes, it is hard-coded somewhere.

I will try to change it once I have more time.

The core code for quick_orm has only 200+ lines, if you want, you can read
it and try to figure out a solution.

Best Regards,

Tyler Long

On Thu, Feb 21, 2013 at 5:15 PM, pengqi notifications@github.com wrote:

Hello,

I tried to change the "id" column to "_id", but failed. The exception is
as following:
sqlalchemy.exc.NoReferencedColumnError: Could not create ForeignKey '
users.id' on table 'posts': table 'users' has no column named 'id'

It seems there is other hard-coded in the library.

The code is as following:

coding: utf-8# test.py

https://github.com/tylerlong/quick_orm# pip install quick_ormfrom quick_orm.core import MyDeclarativeMeta, Database, StringUtil, modelsfrom sqlalchemy import Column, String, Text, Integer, DateTime

class myMeta(MyDeclarativeMeta):
"""metaclass for all model classes, let model class inherit Database.Base and handle table inheritance. All other model metaclasses are either directly or indirectly derived from this class. """
def new(cls, name, bases, attrs):
# add Database.Base as parent class
bases = list(bases)
if object in bases:
bases.remove(object)
bases.append(Database.Base)
seen = set()
bases = tuple(base for base in bases if not base in seen and not seen.add(base))
    attrs['__tablename__'] = StringUtil.camelcase_to_underscore(name)
    print attrs['__tablename__']
    attrs['_id'] = Column(Integer, primary_key = True)
    attrs['created_at'] = Column(DateTime)
    attrs['updated_at'] = Column(DateTime)
    attrs['_readable_name'] = attrs['__tablename__']
    attrs['_readable_names'] =  attrs['_readable_name'] + 's'
    attrs['_one_to_models'] = attrs['_many_to_models'] = []
    if not '__mapper_args__' in attrs:
        attrs['__mapper_args__'] = {}

    # the for loop bellow handles table inheritance
    for base in [base for base in bases if base in models]:
        if not hasattr(base, 'real_type'):
            base.real_type = Column('real_type', String(24), nullable = False, index = True)
            base.__mapper_args__['polymorphic_on'] = base.real_type
            base.__mapper_args__['polymorphic_identity'] = base._readable_name
        attrs['_id'] = Column(Integer, ForeignKey('{0}._id'.format(base._readable_name), ondelete = "CASCADE"), primary_key = True)
        attrs['__mapper_args__']['polymorphic_identity'] = attrs['_readable_name']
        attrs['__mapper_args__']['inherit_condition'] = attrs['_id'] == base._id

    return MyDeclarativeMeta.__new__(cls, name, bases, attrs)
metaclass = myMeta
class Users :
last_name = Column(String(50))
lfirst_name = Column(String(50))
@Database.foreign_key(Users, ref_name='author', backref_name='posts') class Posts :
title = Column(String(200))
content = Column(Text)
Database.register()
if name == 'main':
db = Database('mysql://root:root@127.0.0.1:3306/webscraping?charset=utf8')
db.create_tables()

Thanks,
Qi

—
Reply to this email directly or view it on GitHubhttps://github.com//issues/9.

Best Regards,

Tyler Long

Home page: http://www.tylerlong.me
Github: https://github.com/tylerlong
Bitbucket: https://bitbucket.org/tylerlong http://bitbucket.org/tylerlong

Answer 2 · 2013-02-22T09:00:45.000Z

Compared to sqlalchemy, quick_orm provides simplicity, but loses
flexibility.

It was designed according to my own programming experience, so I ignored
some rare cases. Currently I am not programming with python, I will try my
best to find some time to review and rewrite quick_orm.

On Fri, Feb 22, 2013 at 4:52 PM, Tyler Long tyler4long@gmail.com wrote:

Yes, it is hard-coded somewhere.

I will try to change it once I have more time.

The core code for quick_orm has only 200+ lines, if you want, you can read
it and try to figure out a solution.

Best Regards,

Tyler Long

On Thu, Feb 21, 2013 at 5:15 PM, pengqi notifications@github.com wrote:
Hello,

I tried to change the "id" column to "_id", but failed. The exception is
as following:
sqlalchemy.exc.NoReferencedColumnError: Could not create ForeignKey '
users.id' on table 'posts': table 'users' has no column named 'id'

It seems there is other hard-coded in the library.

The code is as following:

coding: utf-8# test.py

https://github.com/tylerlong/quick_orm# pip install quick_ormfrom quick_orm.core import MyDeclarativeMeta, Database, StringUtil, modelsfrom sqlalchemy import Column, String, Text, Integer, DateTime

class myMeta(MyDeclarativeMeta):
"""metaclass for all model classes, let model class inherit Database.Base and handle table inheritance. All other model metaclasses are either directly or indirectly derived from this class. """
def new(cls, name, bases, attrs):
# add Database.Base as parent class
bases = list(bases)
if object in bases:
bases.remove(object)
bases.append(Database.Base)
seen = set()
bases = tuple(base for base in bases if not base in seen and not seen.add(base))
    attrs['__tablename__'] = StringUtil.camelcase_to_underscore(name)
    print attrs['__tablename__']
    attrs['_id'] = Column(Integer, primary_key = True)
    attrs['created_at'] = Column(DateTime)
    attrs['updated_at'] = Column(DateTime)
    attrs['_readable_name'] = attrs['__tablename__']
    attrs['_readable_names'] =  attrs['_readable_name'] + 's'
    attrs['_one_to_models'] = attrs['_many_to_models'] = []
    if not '__mapper_args__' in attrs:
        attrs['__mapper_args__'] = {}

    # the for loop bellow handles table inheritance
    for base in [base for base in bases if base in models]:
        if not hasattr(base, 'real_type'):
            base.real_type = Column('real_type', String(24), nullable = False, index = True)
            base.__mapper_args__['polymorphic_on'] = base.real_type
            base.__mapper_args__['polymorphic_identity'] = base._readable_name
        attrs['_id'] = Column(Integer, ForeignKey('{0}._id'.format(base._readable_name), ondelete = "CASCADE"), primary_key = True)
        attrs['__mapper_args__']['polymorphic_identity'] = attrs['_readable_name']
        attrs['__mapper_args__']['inherit_condition'] = attrs['_id'] == base._id

    return MyDeclarativeMeta.__new__(cls, name, bases, attrs)
metaclass = myMeta
class Users :
last_name = Column(String(50))
lfirst_name = Column(String(50))
@Database.foreign_key(Users, ref_name='author', backref_name='posts') class Posts :
title = Column(String(200))
content = Column(Text)
Database.register()
if name == 'main':
db = Database('mysql://root:root@127.0.0.1:3306/webscraping?charset=utf8')
db.create_tables()

Thanks,
Qi

—
Reply to this email directly or view it on GitHubhttps://github.com//issues/9.
Best Regards,

Tyler Long

Home page: http://www.tylerlong.me
Github: https://github.com/tylerlong
Bitbucket: https://bitbucket.org/tylerlonghttp://bitbucket.org/tylerlong

Best Regards,

Tyler Long

Home page: http://www.tylerlong.me
Github: https://github.com/tylerlong
Bitbucket: https://bitbucket.org/tylerlong http://bitbucket.org/tylerlong

Answer 3 · 2013-03-05T06:09:36.000Z

Thanks.

I have added the feature: The "id" filed name can be user-defined now.
https://github.com/pengqi/quick_orm/blob/master/quick_orm/core.py

See following example:

# coding: utf-8
# test.py

# https://github.com/tylerlong/quick_orm
# pip install quick_orm
from quick_orm.core import MyDeclarativeMeta, Database, StringUtil, models
from sqlalchemy import Column, String, Text

__metaclass__ = Database.DefaultMeta

class Users :
    __id__ = 'user_id'
    last_name = Column(String(50))
    first_name = Column(String(50))

@Database.foreign_key(Users, ref_name='author', backref_name='posts') 
class Posts :
    __id__ = 'post_id'
    title = Column(String(200))
    content = Column(Text)

Database.register()

if __name__ == '__main__':
    db = Database('mysql://root:root@127.0.0.1:3306/webscraping?charset=utf8')
    db.create_tables()

    user = Users()
    user.last_name = 'Qi'
    user.first_name = 'Peng'
    db.session.add_then_commit(user)

    post = Posts()
    post.author = user
    post.title = 'Life is short.'
    post.content = 'You need Python.'
    db.session.add_then_commit(post)

Answer 4 · 2013-03-05T13:24:40.000Z

Thank you so much!

I will integrate your code into the quick_orm after reviewing and testing.

On Tue, Mar 5, 2013 at 2:09 PM, pengqi notifications@github.com wrote:

Thanks.

I have added the feature: can custom the "id" filed name now.
https://github.com/pengqi/quick_orm/blob/master/quick_orm/core.py

See following example:

coding: utf-8# test.py

https://github.com/tylerlong/quick_orm# pip install quick_ormfrom quick_orm.core import MyDeclarativeMeta, Database, StringUtil, modelsfrom sqlalchemy import Column, String, Text

metaclass = Database.DefaultMeta
class Users :
id = 'user_id'
last_name = Column(String(50))
first_name = Column(String(50))
@Database.foreign_key(Users, ref_name='author', backref_name='posts') class Posts :
id = 'post_id'
title = Column(String(200))
content = Column(Text)
Database.register()
if name == 'main':
db = Database('mysql://root:root@127.0.0.1:3306/webscraping?charset=utf8')
db.create_tables()
user = Users()
user.last_name = 'Qi'
user.first_name = 'Peng'
db.session.add_then_commit(user)

post = Posts()
post.author = user
post.title = 'Life is short.'
post.content = 'You need Python.'
db.session.add_then_commit(post)
[image: sample]https://f.cloud.github.com/assets/1720794/220104/29a31d74-855b-11e2-98b7-502249baf395.png

—
Reply to this email directly or view it on GitHubhttps://github.com//issues/9#issuecomment-14425183
.

Best Regards,

Tyler Long

Home page: http://www.tylerlong.me
Github: https://github.com/tylerlong
Bitbucket: https://bitbucket.org/tylerlong http://bitbucket.org/tylerlong