Question

我有这两个表：

class Performance(Base):
    __tablename__ = 'performances'
    id_ = Column(Integer, Sequence('performance_id_seq'), primary_key=True)
    competitor_id = Column(Integer, ForeignKey('competitors.id_'), index=True)
    start_date = Column(DateTime, nullable=False, index=True)
    end_date = Column(DateTime, nullable=False, index=True)
    target = Column(Float, nullable=True)
    actual = Column(Float, nullable=True)

    competitor = relationship("Competitor", backref="performances")


class TargetAdjustment(Base):
    __tablename__ = 'target_adjustments'
    id_ = Column(Integer, Sequence('target_adjustments_id_seq'), primary_key=True)
    competitor_id = Column(Integer, index=True)
    start_date = Column(DateTime, nullable=False)
    value = Column(Float, nullable=True)

    __table_args__ = (ForeignKeyConstraint([competitor_id, start_date], [Performance.competitor_id, Performance.start_date]), {})

    performance = relationship('Performance', backref=backref("adjustment", uselist=False))


Index('target_adjustment_index', TargetAdjustment.competitor_id, TargetAdjustment.start_date, unique=True)

（除其他外，但这些是我的问题的关键）

现在我需要从这些表中删除记录，但是当它们都包含记录时我无法删除它们！

我这样做：

competition = competitor.competition

adjustment_query = DBSession.query(TargetAdjustment).filter(
    TargetAdjustment.competitor_id == competitor.id_
).filter(
    or_(
        TargetAdjustment.start_date <= competition.start_date,
        TargetAdjustment.start_date >= competition.end_date
    )
)
# delete any extraneous adjustment data for this competitor
log.warning("before: {}".format(adjustment_query.count()))

adjustment_query.delete()

DBSession.flush()

log.warning("after: {}".format(adjustment_query.count()))

# delete any extraneous performance data for this competitor
DBSession.query(Performance).filter(
    Performance.competitor_id == competitor.id_
).filter(
    or_(
        Performance.start_date <= competition.start_date,
        Performance.end_date >= competition.end_date
    )
).delete()
DBSession.flush()

当我尝试删除“表演”记录时，日志声明表明我删除了等效的'target_adjustments'记录，

WARNI：之前：0

WARNI：之后：0

但我仍然遇到这个错误。

“IntegrityError：（IntegrityError）（1451，'无法删除或更新父行：外键约束失败（target_adjustments，CONSTRAINT target_adjustments_ibfk_1 外键（competitor_id，start_date）参考performances （competitor_id，start_date））'）'从表演中删除 performances.competitor_id =％s AND（performances.start_date＆lt; =％s OR performance.end_date＆gt; =％s）'（1128L，datetime.datetime（2016,3,31， 23,0），datetime.datetime（2016,6,1,23,0））“

为什么我不能删除表演记录？

Answer 1

我解决了。

我的删除查询实际上并未匹配所有记录，因此当我尝试删除性能时，表中仍有调整记录。

更新的代码如下：

adjustment_query = DBSession.query(TargetAdjustment).filter(
    TargetAdjustment.competitor_id == competitor.id_
).filter(
    or_(
        TargetAdjustment.start_date <= competition.start_date,
        TargetAdjustment.start_date >= (competition.end_date - timedelta(days=1)) # adjust to match performance end date query
    )
)

幸运的是，我知道表演总是只有一天 - 现在。

无法删除我的数据库记录

1 个答案: