def get(self, id, pk='id', deleted=False):
        try:
            if pk == 'id':
                id = int(id)
            if deleted:
                spec = {pk: id}
            else:
                spec = {pk: id, 'data': {'$exists': 1}}
            fields = {'_id': 0}
            row = self.db.docs.find_one(spec, fields)
        except Exception as e:
            raise DatabaseException(e)
        if row:
            return Document(**row)
        raise NotFoundError('%s %s not found' % (pk, id))
def _db_schema_sanity_check(engine):
    """Ensure all database tables were created with required parameters.

    :param engine:  SQLAlchemy engine instance for a given database

    """

    if engine.name == 'mysql':
        onlyutf8_sql = ('SELECT TABLE_NAME,TABLE_COLLATION '
                        'from information_schema.TABLES '
                        'where TABLE_SCHEMA=%s and '
                        'TABLE_COLLATION NOT LIKE "%%utf8%%"')

        table_names = [res[0] for res in engine.execute(onlyutf8_sql,
                                                        engine.url.database)]
        if len(table_names) > 0:
            raise ValueError(_('Tables "%s" have non utf8 collation, '
                               'please make sure all tables are CHARSET=utf8'
                               ) % ','.join(table_names))