sqlalchemy-dialects-postgresql-array.markdown

title: sqlalchemy.dialects.postgresql ARRAY Example Code category: page slug: sqlalchemy-dialects-postgresql-array-examples sortorder: 500031007 toc: False sidebartitle: sqlalchemy.dialects.postgresql ARRAY meta: Python example code that shows how to use the ARRAY constant from the sqlalchemy.dialects.postgresql module of the SQLAlchemy project.

ARRAY is a constant within the sqlalchemy.dialects.postgresql module of the SQLAlchemy project.

BIGINT, BIT, DOUBLE_PRECISION, ExcludeConstraint, INTEGER, JSON, TSVECTOR, array, json, and pypostgresql are several other callables with code examples from the same sqlalchemy.dialects.postgresql package.

Example 1 from sqlacodegen

sqlacodegen (PyPI package information) is a tool for reading from an existing relational database to generate code to create SQLAlchemy models based on that database. The project is primarily written and maintained by Alex Grönholm (agronholm) and it is open sourced under the MIT license.

sqlacodegen / sqlacodegen / codegen.py

# codegen.py
from __future__ import unicode_literals, division, print_function, absolute_import

import inspect
import re
import sys
from collections import defaultdict
from importlib import import_module
from inspect import ArgSpec
from keyword import iskeyword

import sqlalchemy
import sqlalchemy.exc
from sqlalchemy import (
    Enum, ForeignKeyConstraint, PrimaryKeyConstraint, CheckConstraint, UniqueConstraint, Table,
    Column, Float)
from sqlalchemy.schema import ForeignKey
from sqlalchemy.sql.sqltypes import NullType
from sqlalchemy.types import Boolean, String
from sqlalchemy.util import OrderedDict

try:
    from sqlalchemy import ARRAY
except ImportError:
~~    from sqlalchemy.dialects.postgresql import ARRAY

try:
    from sqlalchemy import Computed
except ImportError:
    Computed = None

try:
    import geoalchemy2  # noqa: F401
except ImportError:
    pass

_re_boolean_check_constraint = re.compile(r"(?:(?:.*?)\.)?(.*?) IN \(0, 1\)")
_re_column_name = re.compile(r'(?:(["`]?)(?:.*)\1\.)?(["`]?)(.*)\2')
_re_enum_check_constraint = re.compile(r"(?:(?:.*?)\.)?(.*?) IN \((.+)\)")
_re_enum_item = re.compile(r"'(.*?)(?<!\\)'")
_re_invalid_identifier = re.compile(r'[^a-zA-Z0-9_]' if sys.version_info[0] < 3 else r'(?u)\W')


class _DummyInflectEngine(object):
    @staticmethod
    def singular_noun(noun):
        return noun




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


        names.add(name)


class Model(object):
    def __init__(self, table):
        super(Model, self).__init__()
        self.table = table
        self.schema = table.schema

        for column in table.columns:
            if not isinstance(column.type, NullType):
                column.type = self._get_adapted_type(column.type, column.table.bind)

    def _get_adapted_type(self, coltype, bind):
        compiled_type = coltype.compile(bind.dialect)
        for supercls in coltype.__class__.__mro__:
            if not supercls.__name__.startswith('_') and hasattr(supercls, '__visit_name__'):
                kw = {}
                if supercls is Enum:
                    kw['name'] = coltype.name

                new_coltype = coltype.adapt(supercls)
                for key, value in kw.items():
                    setattr(new_coltype, key, value)

~~                if isinstance(coltype, ARRAY):
                    new_coltype.item_type = self._get_adapted_type(new_coltype.item_type, bind)

                try:
                    if new_coltype.compile(bind.dialect) != compiled_type:
                        if not isinstance(new_coltype, Float) and \
                           not (isinstance(new_coltype, ARRAY) and
                                isinstance(new_coltype.item_type, Float)):
                            break
                except sqlalchemy.exc.CompileError:
                    break

                coltype = new_coltype
                if supercls.__name__ != supercls.__name__.upper():
                    break

        return coltype

    def add_imports(self, collector):
        if self.table.columns:
            collector.add_import(Column)

        for column in self.table.columns:
            collector.add_import(column.type)
            if column.server_default:
                if isinstance(column.server_default, Computed):
                    collector.add_literal_import('sqlalchemy', 'Computed')
                else:
                    collector.add_literal_import('sqlalchemy', 'text')

~~            if isinstance(column.type, ARRAY):
                collector.add_import(column.type.item_type.__class__)

        for constraint in sorted(self.table.constraints, key=_get_constraint_sort_key):
            if isinstance(constraint, ForeignKeyConstraint):
                if len(constraint.columns) > 1:
                    collector.add_literal_import('sqlalchemy', 'ForeignKeyConstraint')
                else:
                    collector.add_literal_import('sqlalchemy', 'ForeignKey')
            elif isinstance(constraint, UniqueConstraint):
                if len(constraint.columns) > 1:
                    collector.add_literal_import('sqlalchemy', 'UniqueConstraint')
            elif not isinstance(constraint, PrimaryKeyConstraint):
                collector.add_import(constraint)

        for index in self.table.indexes:
            if len(index.columns) > 1:
                collector.add_import(index)

    @staticmethod
    def _convert_to_valid_identifier(name):
        assert name, 'Identifier cannot be empty'
        if name[0].isdigit() or iskeyword(name):
            name = '_' + name
        elif name == 'metadata':


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

Example 2 from sqlalchemy-utils

sqlalchemy-utils (project documentation and PyPI package information) is a code library with various helper functions and new data types that make it easier to use SQLAlchemy when building projects that involve more specific storage requirements such as currency. The wide array of data types includes ranged values and aggregated attributes.

sqlalchemy-utils / sqlalchemy_utils / asserts.py

# asserts.py
from decimal import Decimal

import sqlalchemy as sa
~~from sqlalchemy.dialects.postgresql import ARRAY
from sqlalchemy.exc import DataError, IntegrityError


def _update_field(obj, field, value):
    session = sa.orm.object_session(obj)
    column = sa.inspect(obj.__class__).columns[field]
    query = column.table.update().values(**{column.key: value})
    session.execute(query)
    session.flush()


def _expect_successful_update(obj, field, value, reraise_exc):
    try:
        _update_field(obj, field, value)
    except (reraise_exc) as e:
        session = sa.orm.object_session(obj)
        session.rollback()
        assert False, str(e)


def _expect_failing_update(obj, field, value, expected_exc):
    try:
        _update_field(obj, field, value)
    except expected_exc:
        pass
    else:
        raise AssertionError('Expected update to raise %s' % expected_exc)
    finally:
        session = sa.orm.object_session(obj)
        session.rollback()


def _repeated_value(type_):
~~    if isinstance(type_, ARRAY):
        if isinstance(type_.item_type, sa.Integer):
            return [0]
        elif isinstance(type_.item_type, sa.String):
            return [u'a']
        elif isinstance(type_.item_type, sa.Numeric):
            return [Decimal('0')]
        else:
            raise TypeError('Unknown array item type')
    else:
        return u'a'


def _expected_exception(type_):
~~    if isinstance(type_, ARRAY):
        return IntegrityError
    else:
        return DataError


def assert_nullable(obj, column):
    _expect_successful_update(obj, column, None, IntegrityError)


def assert_non_nullable(obj, column):
    _expect_failing_update(obj, column, None, IntegrityError)


def assert_max_length(obj, column, max_length):
    type_ = sa.inspect(obj.__class__).columns[column].type
    _expect_successful_update(
        obj,
        column,
        _repeated_value(type_) * max_length,
        _expected_exception(type_)
    )
    _expect_failing_update(
        obj,
        column,


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