[英]SQLAlchemy Many-to-many table with multiple foreign key entires
我是sqlalchemy的新手,我想盡可能簡單但正確地做到這一點。 我想每月跟蹤多個公司之間的域名使用情況,因此我設置了以下表格:
class Company(Base):
__tablename__ = 'company'
id = Column(Integer, primary_key = True)
name = Column('name', String)
class Domains(Base):
__tablename__ = 'domains'
id = Column(Integer, primary_key=True)
name = Column('name', String, unique=True)
class MonthlyUsage(Base):
'''
Track domain usage across all
companies on a monthly basis.
'''
__tablename__ = 'monthlyusage'
month = Column(DateTime)
company_id = Column(Integer, ForeignKey('company.id'))
domain_id = Column(Integer, ForeignKey('domains.id'))
# <...other columns snipped out...>
company = relationship('Company', backref='company_assoc')
domain = relationship('Domains', backref='domain_assoc')
在我添加第二個月的使用詳細信息之前,該方法可以正常工作。 然后,我得到重復的鍵值錯誤:
* sqlalchemy.exc.IntegrityError:(IntegrityError)重復鍵值違反了唯一約束“ monthlyusage_pkey” *
這是否意味着我必須將“每月使用量”分成第三張表? 這似乎不必要地復雜,因為唯一需要的是月份,company_id和domain_id字段。
對我的布局有什么建議,以使其盡可能簡單但仍然正確?
TIA!
好的,我需要向MonthlyUsage添加一個主鍵列。 下面的代碼現在可以工作了...
class MonthlyUsage(Base):
'''
Track domain usage across all
companies on a monthly basis.
'''
__tablename__ = 'monthlyusage'
month = Column(DateTime)
month_id = Column(Integer, primary_key=True)
company_id = Column(Integer, ForeignKey('company.id'), primary_key=True)
domain_id = Column(Integer, ForeignKey('domains.id'), primary_key=True)
# <...other columns snipped out...>
company = relationship('Company', backref='company_assoc')
domain = relationship('Domains', backref='domain_assoc')
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