Source code for sqlalchemy_utils.types.scalar_list

import six
import sqlalchemy as sa
from sqlalchemy import types


class ScalarListException(Exception):
    pass


[docs]class ScalarListType(types.TypeDecorator): """ ScalarListType type provides convenient way for saving multiple scalar values in one column. ScalarListType works like list on python side and saves the result as comma-separated list in the database (custom separators can also be used). Example :: from sqlalchemy_utils import ScalarListType class User(Base): __tablename__ = 'user' id = sa.Column(sa.Integer, autoincrement=True) hobbies = sa.Column(ScalarListType()) user = User() user.hobbies = [u'football', u'ice_hockey'] session.commit() You can easily set up integer lists too: :: from sqlalchemy_utils import ScalarListType class Player(Base): __tablename__ = 'player' id = sa.Column(sa.Integer, autoincrement=True) points = sa.Column(ScalarListType(int)) player = Player() player.points = [11, 12, 8, 80] session.commit() """ impl = sa.UnicodeText() def __init__(self, coerce_func=six.text_type, separator=u','): self.separator = six.text_type(separator) self.coerce_func = coerce_func def process_bind_param(self, value, dialect): # Convert list of values to unicode separator-separated list # Example: [1, 2, 3, 4] -> u'1, 2, 3, 4' if value is not None: if any(self.separator in six.text_type(item) for item in value): raise ScalarListException( "List values can't contain string '%s' (its being used as " "separator. If you wish for scalar list values to contain " "these strings, use a different separator string.)" % self.separator ) return self.separator.join( map(six.text_type, value) ) def process_result_value(self, value, dialect): if value is not None: if value == u'': return [] # coerce each value return list(map( self.coerce_func, value.split(self.separator) ))