sqlalchemy-orm-mapper-mapper.markdown

title: sqlalchemy.orm.mapper Mapper Example Code category: page slug: sqlalchemy-orm-mapper-mapper-examples sortorder: 500031085 toc: False sidebartitle: sqlalchemy.orm.mapper Mapper meta: Example code for understanding how to use the Mapper class from the sqlalchemy.orm.mapper module of the SQLAlchemy project.

Mapper is a class within the sqlalchemy.orm.mapper module of the SQLAlchemy project.

Example 1 from SQLAlchemy filters

SQLAlchemy filters provides filtering, sorting and pagination for SQLAlchemy query objects, which is particularly useful when building web APIs. SQLAlchemy filters is open sourced under the Apache License version 2.0.

SQLAlchemy filters / sqlalchemy_filters / models.py

# models.py
from sqlalchemy.exc import InvalidRequestError
from sqlalchemy.inspection import inspect
~~from sqlalchemy.orm.mapper import Mapper
from sqlalchemy.util import symbol
import types

from .exceptions import BadQuery, FieldNotFound, BadSpec


class Field(object):

    def __init__(self, model, field_name):
        self.model = model
        self.field_name = field_name

    def get_sqlalchemy_field(self):
        if self.field_name not in self._get_valid_field_names():
            raise FieldNotFound(
                'Model {} has no column `{}`.'.format(
                    self.model, self.field_name
                )
            )
        sqlalchemy_field = getattr(self.model, self.field_name)

        if isinstance(sqlalchemy_field, types.MethodType):
            sqlalchemy_field = sqlalchemy_field()



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