Source code for kadi.lib.tags.models

# Copyright 2020 Karlsruhe Institute of Technology
# 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
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# See the License for the specific language governing permissions and
# limitations under the License.
from sqlalchemy.exc import IntegrityError

from kadi.ext.db import db
from kadi.lib.db import NestedTransaction
from kadi.lib.db import generate_check_constraints
from kadi.lib.utils import SimpleReprMixin

[docs]class Tag(SimpleReprMixin, db.Model): """Model to represent tags."""
[docs] class Meta: """Container to store meta class attributes.""" representation = ["id", "name"] """See :class:`.SimpleReprMixin`.""" check_constraints = { "name": {"length": {"max": 50}}, } """See :func:`kadi.lib.db.generate_check_constraints`."""
__tablename__ = "tag" __table_args__ = generate_check_constraints(Meta.check_constraints) id = db.Column(db.Integer, primary_key=True) """The ID of the tag, auto incremented.""" name = db.Column(db.Text, index=True, unique=True, nullable=False) """The unique name of the tag. Restricted to a maximum length of ``50`` characters. """ records = db.relationship( "Record", secondary="record_tag", lazy="dynamic", back_populates="tags" ) collections = db.relationship( "Collection", secondary="collection_tag", lazy="dynamic", back_populates="tags" )
[docs] @classmethod def create(cls, *, name): """Create a new tag and add it to the database session. :param name: The name of the tag. :return: The new :class:`Tag` object. """ tag = cls(name=name) db.session.add(tag) return tag
[docs] @classmethod def get_or_create(cls, name): """Return an existing tag or create one if it does not exist yet. See :meth:`create` for an explanation of the parameters. :return: The new or existing :class:`.Tag` object. """ tag_query = cls.query.filter_by(name=name) tag = tag_query.first() if not tag: with NestedTransaction(exc=IntegrityError) as t: tag = cls.create(name=name) if not t.success: tag = tag_query.first() return tag