from app.extensions import db


class BomDraftTable(db.Model):
    __tablename__ = 'bom_draft_table'

    id = db.Column(db.Integer, primary_key=True)
    bom_no = db.Column(db.String(100), nullable=False, index=True, comment='BOM编号')
    version = db.Column(db.String(50), nullable=False, default='V1.0', index=True, comment='版本')
    parent_id = db.Column(
        db.Integer,
        db.ForeignKey('material_base.id', ondelete='SET NULL'),
        nullable=True,
        comment='父件物料ID'
    )
    child_id = db.Column(
        db.Integer,
        db.ForeignKey('material_base.id', ondelete='SET NULL'),
        nullable=True,
        comment='子件物料ID'
    )
    dosage = db.Column(db.Numeric(19, 4), comment='个数')
    loss_rate = db.Column(db.Numeric(5, 2), default=0, nullable=True, comment='损耗率%')
    remark = db.Column(db.Text, comment='备注')
    updated_at = db.Column(db.DateTime, default=db.func.now(), onupdate=db.func.now(), comment='更新时间')

    parent = db.relationship(
        'MaterialBase',
        foreign_keys=[parent_id],
        backref='bom_draft_parents',
        passive_deletes=True
    )
    child = db.relationship(
        'MaterialBase',
        foreign_keys=[child_id],
        backref='bom_draft_children',
        passive_deletes=True
    )