document-management/backend/dms/models/document_relation.py

"""方案关联关系模型（方案与其关联方案间的有向声明）。"""

from __future__ import annotations

from sqlalchemy import (
    BigInteger,
    CheckConstraint,
    Computed,
    ForeignKey,
    Index,
    Integer,
    String,
    UniqueConstraint,
    text,
)
from sqlalchemy.orm import Mapped, mapped_column

from dms.database.base import BusinessTableMixin
from dms.extensions import db


class DocumentRelation(BusinessTableMixin, db.Model):
    __tablename__ = "doc_document_relation"
    __table_args__ = (
        CheckConstraint(
            "document_id <> related_document_id",
            name="document_relation_no_self",
        ),
        UniqueConstraint(
            "document_id",
            "related_document_id",
            "active_marker",
            name="uq_doc_document_relation_active",
        ),
        Index(
            "ix_doc_document_relation_document_active_sort",
            "document_id",
            "is_deleted",
            "sort_no",
        ),
        Index(
            "ix_doc_document_relation_related_active",
            "related_document_id",
            "is_deleted",
        ),
    )

    document_id: Mapped[int] = mapped_column(
        BigInteger,
        ForeignKey("doc_document.id", ondelete="RESTRICT"),
        nullable=False,
    )
    related_document_id: Mapped[int] = mapped_column(
        BigInteger,
        ForeignKey("doc_document.id", ondelete="RESTRICT"),
        nullable=False,
    )
    relation_type: Mapped[str] = mapped_column(String(64), nullable=False)
    sort_no: Mapped[int] = mapped_column(
        Integer,
        nullable=False,
        server_default=text("0"),
    )
    active_marker: Mapped[int | None] = mapped_column(
        Integer,
        Computed("IF(is_deleted = 0, 1, NULL)", persisted=False),
        nullable=True,
    )