Selecting fields

By default SQLAlchemy-JSON-API selects all orm descriptors (except synonyms) for given model. This includes:

• Column properties
• Hybrid properties
• Relationship properties

Please notice that you can’t include regular descriptors, only orm descriptors.

The id property

Each included model MUST have an id property. Usually this should be the primary key of your model. If your model doesn’t have an id property you can add one by using for example SQLAlchemy hybrids.

from sqlalchemy.ext.hybrid import hybrid_property


class GroupInvitation(Base):
    group_id = sa.Column(
        sa.Integer,
        sa.ForeignKey(Group.id),
        primary_key=True
    )
    user_id = sa.Column(
        sa.Integer,
        sa.ForeignKey(User.id),
        primary_key=True
    )
    issued_at = sa.Column(sa.DateTime)

    @hybrid_property
    def id(self):
        return self.group_id + ':' + self.user_id

Note

SQLAlchemy-JSON-API always returns the id as a string. If the type of the id property is not a string SQLAlchemy-JSON-API tries to cast the given property to string.

Customizing field selection

You can customize this behaviour by providing the fields parameter to QueryBuilder.select().

query_builder.select(Article, fields={'articles': ['name']})
result = session.execute(query).scalar()
# {
#     'data': [{
#         'id': '1',
#         'type': 'articles',
#         'attributes': {
#             'name': 'Some article',
#         },
#     }]
# }

If you only want to select id for given model you need to provide empty list for given model key.

query = query_builder.select(Article, fields={'articles': []})
result = session.execute(query).scalar()
# {
#     'data': [{
#         'id': '1',
#         'type': 'articles',
#     }]
# }