sqlalchemy.orm.properties ColumnProperty Example Code

# orm.py
from collections import OrderedDict
from functools import partial
from inspect import isclass
from operator import attrgetter

import six
import sqlalchemy as sa
from sqlalchemy.engine.interfaces import Dialect
from sqlalchemy.ext.hybrid import hybrid_property
from sqlalchemy.orm import mapperlib
from sqlalchemy.orm.attributes import InstrumentedAttribute
from sqlalchemy.orm.exc import UnmappedInstanceError
from sqlalchemy.orm.properties import ColumnProperty, RelationshipProperty
from sqlalchemy.orm.query import _ColumnEntity
from sqlalchemy.orm.session import object_session
from sqlalchemy.orm.util import AliasedInsp

from ..utils import is_sequence


def get_class_by_table(base, table, data=None):
    found_classes = set(
        c for c in base._decl_class_registry.values()
        if hasattr(c, '__table__') and c.__table__ is table
    )
    if len(found_classes) > 1:
        if not data:
            raise ValueError(
                "Multiple declarative classes found for table '{0}'. "
                "Please provide data parameter for this function to be able "
                "to determine polymorphic scenarios.".format(
                    table.name
                )
            )
        else:
            for cls in found_classes:
                mapper = sa.inspect(cls)
                polymorphic_on = mapper.polymorphic_on.name
                if polymorphic_on in data:
                    if data[polymorphic_on] == mapper.polymorphic_identity:
                        return cls
            raise ValueError(
                "Multiple declarative classes found for table '{0}'. Given "
                "data row does not match any polymorphic identity of the "
                "found classes.".format(
                    table.name
                )
            )
    elif found_classes:
        return found_classes.pop()
    return None


def get_type(expr):
    if hasattr(expr, 'type'):
        return expr.type
    elif isinstance(expr, InstrumentedAttribute):
        expr = expr.property

    if isinstance(expr, ColumnProperty):
        return expr.columns[0].type
    elif isinstance(expr, RelationshipProperty):
        return expr.mapper.class_
    raise TypeError("Couldn't inspect type.")


def cast_if(expression, type_):
    try:
        expr_type = get_type(expression)
    except TypeError:
        expr_type = expression
        check_type = type_().python_type
    else:
        check_type = type_

    return (
        sa.cast(expression, type_)
        if not isinstance(expr_type, check_type)
        else expression
    )


def get_column_key(model, column):
    mapper = sa.inspect(model)


## ... source file abbreviated to get to ColumnProperty examples ...


        return [mixed.table]
    elif isinstance(mixed, sa.orm.attributes.InstrumentedAttribute):
        return mixed.parent.tables
    elif isinstance(mixed, sa.orm.query._ColumnEntity):
        mixed = mixed.expr

    mapper = get_mapper(mixed)

    polymorphic_mappers = get_polymorphic_mappers(mapper)
    if polymorphic_mappers:
        tables = sum((m.tables for m in polymorphic_mappers), [])
    else:
        tables = mapper.tables
    return tables


def get_columns(mixed):
    if isinstance(mixed, sa.sql.selectable.Selectable):
        return mixed.c
    if isinstance(mixed, sa.orm.util.AliasedClass):
        return sa.inspect(mixed).mapper.columns
    if isinstance(mixed, sa.orm.Mapper):
        return mixed.columns
    if isinstance(mixed, InstrumentedAttribute):
        return mixed.property.columns
    if isinstance(mixed, ColumnProperty):
        return mixed.columns
    if isinstance(mixed, sa.Column):
        return [mixed]
    if not isclass(mixed):
        mixed = mixed.__class__
    return sa.inspect(mixed).columns


def table_name(obj):
    class_ = getattr(obj, 'class_', obj)

    try:
        return class_.__tablename__
    except AttributeError:
        pass

    try:
        return class_.__table__.name
    except AttributeError:
        pass


def getattrs(obj, attrs):
    return map(partial(getattr, obj), attrs)


## ... source file abbreviated to get to ColumnProperty examples ...


def get_query_descriptor(query, entity, attr):
    if attr in query_labels(query):
        return attr
    else:
        entity = get_query_entity_by_alias(query, entity)
        if entity:
            descriptor = get_descriptor(entity, attr)
            if (
                hasattr(descriptor, 'property') and
                isinstance(descriptor.property, sa.orm.RelationshipProperty)
            ):
                return
            return descriptor


def get_descriptor(entity, attr):
    mapper = sa.inspect(entity)

    for key, descriptor in get_all_descriptors(mapper).items():
        if attr == key:
            prop = (
                descriptor.property
                if hasattr(descriptor, 'property')
                else None
            )
            if isinstance(prop, ColumnProperty):
                if isinstance(entity, sa.orm.util.AliasedClass):
                    for c in mapper.selectable.c:
                        if c.key == attr:
                            return c
                else:
                    return getattr(prop.parent.class_, attr)
            else:

                if isinstance(entity, sa.orm.util.AliasedClass):
                    return getattr(entity, attr)
                try:
                    return getattr(mapper.class_, attr)
                except AttributeError:
                    pass


def get_all_descriptors(expr):
    if isinstance(expr, sa.sql.selectable.Selectable):
        return expr.c
    insp = sa.inspect(expr)
    try:
        polymorphic_mappers = get_polymorphic_mappers(insp)
    except sa.exc.NoInspectionAvailable:
        return get_mapper(expr).all_orm_descriptors


## ... source file continues with no further ColumnProperty examples...

# generator.py
import inspect
from collections import OrderedDict
from decimal import Decimal
from enum import Enum

import six
import sqlalchemy as sa
from sqlalchemy.orm.properties import ColumnProperty
from sqlalchemy_utils import types
from wtforms import (
    BooleanField,
    Field,
    FloatField,
    PasswordField,
    TextAreaField
)
from wtforms.widgets import CheckboxInput, TextArea
from wtforms_components import (
    ColorField,
    DateField,
    DateIntervalField,
    DateTimeField,
    DateTimeIntervalField,
    DateTimeLocalField,
    DecimalField,
    DecimalIntervalField,
    EmailField,
    IntegerField,
    IntIntervalField,
    SelectField,
    StringField,
    TimeField


## ... source file abbreviated to get to ColumnProperty examples ...



    WIDGET_MAP = OrderedDict((
        (BooleanField, CheckboxInput),
        (ColorField, ColorInput),
        (DateField, DateInput),
        (DateTimeField, DateTimeInput),
        (DateTimeLocalField, DateTimeLocalInput),
        (DecimalField, NumberInput),
        (EmailField, EmailInput),
        (FloatField, NumberInput),
        (IntegerField, NumberInput),
        (TextAreaField, TextArea),
        (TimeField, TimeInput),
        (StringField, TextInput)
    ))

    def __init__(self, form_class):
        self.form_class = form_class
        self.model_class = self.form_class.Meta.model
        self.meta = self.form_class.Meta
        self.TYPE_MAP.update(self.form_class.Meta.type_map)

    def create_form(self, form):
        attrs = OrderedDict()
        for key, property_ in sa.inspect(self.model_class).attrs.items():
            if not isinstance(property_, ColumnProperty):
                continue
            if self.skip_column_property(property_):
                continue
            attrs[key] = property_

        for attr in translated_attributes(self.model_class):
            attrs[attr.key] = attr.property

        return self.create_fields(form, self.filter_attributes(attrs))

    def filter_attributes(self, attrs):
        if self.meta.only:
            attrs = OrderedDict([
                (key, prop)
                for key, prop in map(self.validate_attribute, self.meta.only)
                if key
            ])
        else:
            if self.meta.include:
                attrs.update([
                    (key, prop)
                    for key, prop
                    in map(self.validate_attribute, self.meta.include)
                    if key


## ... source file abbreviated to get to ColumnProperty examples ...



            if self.meta.exclude:
                for key in self.meta.exclude:
                    try:
                        del attrs[key]
                    except KeyError:
                        if self.meta.attr_errors:
                            raise InvalidAttributeException(key)
        return attrs

    def validate_attribute(self, attr_name):
        try:
            attr = getattr(self.model_class, attr_name)
        except AttributeError:
            try:
                translation_class = (
                    self.model_class.__translatable__['class']
                )
                attr = getattr(translation_class, attr_name)
            except AttributeError:
                if self.meta.attr_errors:
                    raise InvalidAttributeException(attr_name)
                else:
                    return None, None
        try:
            if not isinstance(attr.property, ColumnProperty):
                if self.meta.attr_errors:
                    raise InvalidAttributeException(attr_name)
                else:
                    return None, None
        except AttributeError:
            raise AttributeTypeException(attr_name)
        return attr_name, attr.property

    def create_fields(self, form, properties):
        for key, prop in properties.items():
            column = prop.columns[0]
            try:
                field = self.create_field(prop, column)
            except UnknownTypeException:
                if not self.meta.skip_unknown_types:
                    raise
                else:
                    continue

            if not hasattr(form, key):
                setattr(form, key, field)

    def skip_column_property(self, column_property):
        if column_property._is_polymorphic_discriminator:


## ... source file continues with no further ColumnProperty examples...