d2a 1.0.1

It converts django models to a sqlalchemy orm/expression objects.

It converts django models to sqlalchemy orm/expression objects.

Requirements

• Python: 2.7, 3.3, 3.4, 3.5, 3.6 (Tested with 2.7, 3.6)

• Django: 1.9 ~ 2.0 (Tested with 1.11, 2.0)

• SQLAlchemy: 0.9 ~ 1.2 (Tested with 1.2)

Installation

$ pip install d2a

Usage

altogether

Example: you make models_sqla.py at the same directory which models.py has been placed on.

• And write like the following to the models_sqla.py

  from d2a import transfer
  from . import models
  transfer(models, globals())

  • Example:

    • project_postgresql/books/models_sqla.py

    • project_postgresql/sales/models_sqla.py

    • You can omit specifying db_type, then it automatically detects database type from settings.DATABASES['default'].

      • Allowed db_type is now postgresql, mysql and oracle, the other types will be converted to the following types as default type: sqlalchemy/types.py

That’s all, you can import sqlalchemy declaration made from django model.

>>> from books import models
>>> models.  # tab completion
models.ArrayField(        models.Book(              models.CategoryRelation(  models.models
models.Author(            models.Category(          models.JSONField(         models.uuid

>>> models.Book
<class 'books.models.Book'>

>>> models.Book.
models.Book.DoesNotExist(             models.Book.delete(                   models.Book.refresh_from_db(
models.Book.MultipleObjectsReturned(  models.Book.description               models.Book.sales
models.Book.add_to_class(             models.Book.from_db(                  models.Book.save(
models.Book.author                    models.Book.full_clean(               models.Book.save_base(
models.Book.author_id                 models.Book.get_deferred_fields(      models.Book.serializable_value(
models.Book.category                  models.Book.id                        models.Book.tags
models.Book.check(                    models.Book.mro(                      models.Book.title
models.Book.clean(                    models.Book.objects                   models.Book.unique_error_message(
models.Book.clean_fields(             models.Book.pk                        models.Book.validate_unique(
models.Book.content                   models.Book.prepare_database_save(
models.Book.date_error_message(       models.Book.price
>>> from books import models_sqla
>>> models_sqla.  # tab completion
models_sqla.Author(            models_sqla.BookCategory(      models_sqla.CategoryRelation(  models_sqla.transfer(
models_sqla.Book(              models_sqla.Category(          models_sqla.models

>>> models_sqla.Book
<class 'd2a.book'>

>>> models_sqla.Book.  # tab completion
models_sqla.Book.author       models_sqla.Book.content      models_sqla.Book.metadata     models_sqla.Book.tags
models_sqla.Book.author_id    models_sqla.Book.description  models_sqla.Book.mro(         models_sqla.Book.title
models_sqla.Book.category     models_sqla.Book.id           models_sqla.Book.price
# SQL Expression schema
>>> models_sqla.Book.__table__
Table(
  'book', MetaData(bind=None),
  Column('id', UUID(), table=<book>, primary_key=True, nullable=False, default=ColumnDefault(<function uuid4 at 0x7f3cebe7e598>)),
  Column('price', JSON(astext_type=Text()), table=<book>, nullable=False, default=ColumnDefault(<function NOT_PROVIDED at 0x7f3cebe7ebf8>)),
  Column('title', VARCHAR(length=255), table=<book>, nullable=False, default=ColumnDefault(<function NOT_PROVIDED at 0x7f3cebe7ec80>)),
  Column('description', TEXT(), table=<book>, default=ColumnDefault(<function NOT_PROVIDED at 0x7f3cebe7ed08>)),
  Column('author_id', INTEGER(), ForeignKey('author.id'), table=<book>, default=ColumnDefault(<function NOT_PROVIDED at 0x7f3cebe7ed90>)),
  Column('content', BYTEA(), table=<book>, nullable=False, default=ColumnDefault(<function NOT_PROVIDED at 0x7f3cebe7ee18>)),
  Column('tags', ARRAY(VARCHAR()), table=<book>, nullable=False, default=ColumnDefault(<function NOT_PROVIDED at 0x7f3cebe7eea0>)),
  schema=None
)

Also, it can extract model declared implicitly depending on m2m field. (in this case, BookCategory)

single

If you just want to convert one model, you should use declare function

>>> from d2a import declare
>>> from sales.models import Sales
>>> sales = declare(Sales)
>>> sales
<class 'd2a.sales'>

>>> sales.__table__
Table(
  'sales', MetaData(bind=None),
  Column('id', BIGINT(), table=<sales>, primary_key=True, nullable=False, default=ColumnDefault(<function NOT_PROVIDED at 0x7f3cebdebf28>)),
  Column('book_id', UUID(), ForeignKey('book.id'), table=<sales>, nullable=False, default=ColumnDefault(<function NOT_PROVIDED at 0x7f3cebdebea0>)),
  Column('sold', TIMESTAMP(), table=<sales>, nullable=False, default=ColumnDefault(<function NOT_PROVIDED at 0x7f3cebdeb730>)),
  Column('reservation', INTERVAL(), table=<sales>, default=ColumnDefault(<function NOT_PROVIDED at 0x7f3cebdeb6a8>)),
  Column('source', INET(), table=<sales>, default=ColumnDefault(<function NOT_PROVIDED at 0x7f3cebdeb620>)),
  schema=None
)

>>> sales.
sales.book         sales.id           sales.mro(         sales.sold
sales.book_id      sales.metadata     sales.reservation  sales.source

Custom fields

If you are using customized field which is not built-in, you can register the field as the other field using alias method.

from django.db.models import ImageField

class ExtendedImageField(ImageField):
    """something customizing"""

from d2a import alias
alias(ExtendedImageField, ImageField)

Demo

start up environment

$ git clone [e-mail]:righ/d2a.git
$ cd d2a
$ docker-compose up

preparation

$ docker exec -it d2a_app_1 /bin/bash
# python -m venv venv # only first time
# source venv/bin/activate
(venv) # cd project_postgresql/ # (or mysql)
(venv) project_postgresql # ./manage.py migrate

execute

(venv) project_postgresql # ./manage.py shell

>>> from books import models_sqla
>>> book = models_sqla.Book()
>>> author = models_sqla.Author()
>>> book.author = author
>>> author.books
[<d2a.book object at 0x7f3cec539358>]
# And do something you want do ;)

Links

• https://github.com/righ/d2a

History

1.0.1:

• (2018-07-06)

• Fixed a bug, that it will be provided None even though it does not be specified default argument.

1.0.0:

• (2018-07-05)

• Fixed bugs.

• Added unit tests.

0.0.6:

• Fixed a bug that abstract models become the targets.

• Deleted install_requires.

0.0.5:

• added alias method.

0.0.4:

• fixed bugs.

0.0.3:

• it got easy to declare custom field.

• transfer method can define secondary table.

0.0.2:

• it supported m2m field.

• it limited django version less than 1.9.

0.0.1:

first release (2017-12-27)