# Copyright 2019 Google LLC

#

# Licensed under the Apache License, Version 2.0 (the "License");

# you may not use this file except in compliance with the License.

# You may obtain a copy of the License at

#

# https://www.apache.org/licenses/LICENSE-2.0

#

# Unless required by applicable law or agreed to in writing, software

# distributed under the License is distributed on an "AS IS" BASIS,

# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

# See the License for the specific language governing permissions and

# limitations under the License.

"""Represents an index on a Model."""

from typing import List, Optional

from spanner_orm import error

class Index:

"""Represents an index on a Model."""

PRIMARY_INDEX = 'PRIMARY_KEY'

def __init__(self,

columns: List[str],

parent: Optional[str] = None,

null_filtered: bool = False,

unique: bool = False,

storing_columns: Optional[List[str]] = None):

if not columns:

raise error.ValidationError('An index must have at least one column')

self.columns = columns

self.name = None

self.parent = parent

self.null_filtered = null_filtered

self.unique = unique

self.storing_columns = storing_columns or []

@property

def primary(self) -> bool:

return self.name == self.PRIMARY_INDEX