django_sorcery.db.relations module

sqlalchemy relationship related things.

class django_sorcery.db.relations.RelationsMixin

Bases: object

Mixin that provides django like shortcuts for relationships.

ManyToMany(remote_cls, table_name=None, **kwargs)

Use an event to build many-to-many relationship on a model and auto generates an association table or if a model is provided as secondary argument:

class ModelOne(db.Model):
    pk = db.Column(.., primary_key=True)
    m2s = db.ManyToMany("ModelTwo", backref="m1s", table_name='m1m2s', ...)

class ModelTwo(db.Model):
    pk = db.Column(.., primary_key=True)
    ...

or with back_populates:

class ModelOne(db.Model):
    pk = db.Column(.., primary_key=True)
    m2s = db.ManyToMany("ModelTwo", back_populates="m1s", table_name='m1m2s', ...)

class ModelTwo(db.Model):
    pk = db.Column(.., primary_key=True)
    m1s = db.ManyToMany("ModelOne", back_populates="m2s", table_name='m1m2s', ...)

will create ModelOne.m2s and ModelTwo.m1s relationship thru a provided secondary argument. If no secondary argument is provided, table_name is required as it will be used for the autogenerated association table.

In the case of back_populates you have to provide the same table_name argument on both many-to-many declarations

ManyToOne(remote_cls, **kwargs)

Use an event to build many-to-one relationship on a model and auto generates foreign key relationship on the remote table:

class ModelOne(db.Model):
    pk = db.Column(.., primary_key=True)
    m2 = db.ManyToOne("ModelTwo", ...)

class ModelTwo(db.Model):
    pk = db.Column(.., primary_key=True)
    ...

will create ModelOne.m2_pk automatically for the relationship

OneToMany(remote_cls, **kwargs)

Use an event to build one-to-many relationship on a model and auto generates foreign key relationship from the remote table:

class ModelOne(db.Model):

pk = db.Column(.., primary_key=True) m2 = db.OneToMany(“ModelTwo”, …)

class ModelTwo(db.Model):

pk = db.Column(.., primary_key=True) …

will create ModelTwo.m1_pk automatically for the relationship

OneToOne(remote_cls, **kwargs)

Use an event to build one-to-many relationship on a model and auto generates foreign key relationship from the remote table:

class ModelOne(db.Model):

pk = db.Column(.., primary_key=True) m2 = db.OneToOne(“ModelTwo”, …)

class ModelTwo(db.Model):

pk = db.Column(.., primary_key=True) …

will create ModelTwo.m1_pk automatically for the relationship

django_sorcery.db.relations.declare_first_relationships_handler(cls)

Declare first signal handler which connects relationships on the class.

Can be called multiple times so once relationships are set, they are removed from model