Source code for invenio_records.models

# -*- coding: utf-8 -*-
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"""Record models."""

import uuid

from invenio_db import db
from sqlalchemy.dialects import postgresql
from sqlalchemy_utils.models import Timestamp
from sqlalchemy_utils.types import JSONType, UUIDType


class RecordMetadata(db.Model, Timestamp):
    """Represent a record metadata inside the SQL database.

    Additionally it contains two columns ``created`` and ``updated``
    with automatically managed timestamps.
    """

    # Enables SQLAlchemy-Continuum versioning
    __versioned__ = {}

    __tablename__ = 'records_metadata'

    id = db.Column(
        UUIDType,
        primary_key=True,
        default=uuid.uuid4,
    )
    """Record identifier."""

    json = db.Column(
        JSONType().with_variant(
            postgresql.JSON(none_as_null=True),
            'postgresql',
        ),
        default=lambda: dict(),
        nullable=True
    )
    """Store metadata in JSON format.

    When you create new ``Record`` the ``json`` field value should
    never be ``NULL``.  Default value is an empty dict.  ``NULL``
    value means that the record metadata has been deleted.
    """

    version_id = db.Column(db.Integer, nullable=False)
    """It is used by SQLAlchemy for optimistic concurrency control."""

    __mapper_args__ = {
        'version_id_col': version_id
    }


__all__ = (
    'RecordMetadata',
)