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我完全卡在尝试使用SQLAlchemy加入一对多关系。 我的模型看起来是这样的:SQLalchemy加入多对一的关系
class Protein(Base):
__tablename__ = 'protein'
protein_id = Column(Integer, primary_key=True)
gene_name = Column(String(45))
spectrum_hit_spectrum_hits = relationship(u'SpectrumHit', secondary='spectrum_protein_map')
class SpectrumHit(Base):
__tablename__ = 'spectrum_hit'
spectrum_hit_id = Column(Integer, primary_key=True)
sequence = Column(String(60, u'latin1_german1_ci'), index=True)
和映射表:
t_spectrum_protein_map = Table(
'spectrum_protein_map', metadata,
Column('spectrum_hit_spectrum_hit_id', ForeignKey(u'spectrum_hit.spectrum_hit_id'), nullable=False, index=True),
Column('protein_protein_id', ForeignKey(u'protein.protein_id'), nullable=False, index=True)
)
我的查询是:
query = DBSession.query(Protein.gene_name, SpectrumHit.sequence)
query = query.join(SpectrumHit)
result = query.all()
我也试了一下周围的其他方法
query = DBSession.query(SpectrumHit.sequence, Protein.gene_name)
query = query.join(Protein)
result = query.all()
如果有帮助,我也可以添加我的MySQL表。
我总是得到错误:
InvalidRequestError: Could not find a FROM clause to join from. Tried joining to <class 'ligando.models.Protein'>, but got: Can't find any foreign key relationships between 'spectrum_hit' and 'protein'.
这就解释了自己......
如果我尝试做平原的MySQL这个查询它看起来像这样:
SELECT spectrum_hit.sequence, protein.gene_name
From spectrum_hit
join spectrum_protein_map on spectrum_hit.spectrum_hit_id = spectrum_protein_map.spectrum_hit_spectrum_hit_id
join protein on protein.protein_id = spectrum_protein_map.protein_protein_id
而且它的工作
我的元数据对象是全球范围内声明的文件中 元= Base.metadata – Linus
我已经编辑我的反应,包括整个脚本作品对我来说 - 你能发现任何主要的区别吗? – wilfo
我通过明确地将映射表添加到连接中找到了解决方案 query = query.join(t_spectrum_protein_map) 无论如何,谢谢! :) – Linus