sqlalchemy的relationship的基本用法 最后更新时间：2025年01月07日 #### 前言 国内互联网很多sqlalchemy资料搜索出来的都是老版本的操作了。新版本的sqlalchemy使用relationship相当简单，定义过来之后直接像是继承一样的方法直接用即可。 #### 示例 ```python from module.DB.DB import * class RStep(Base): __tablename__ = 'r_step' ID_STEP = Column(BigInteger, nullable = False, primary_key = True) ID_TRANSFORMATION = Column(Integer, nullable = False) NAME = Column(String(255), nullable = False) DESCRIPTION = Column(Text(16777215), nullable = False) ID_STEP_TYPE = Column(Integer, ForeignKey('r_step_type.ID_STEP_TYPE')) DISTRIBUTE = Column(Boolean, nullable = False) COPIES = Column(Integer, nullable = False) GUI_LOCATION_X = Column(Integer, nullable = False) GUI_LOCATION_Y = Column(Integer, nullable = False) GUI_DRAW = Column(Boolean, nullable = False) COPIES_STRING = Column(String(255), nullable = False) r_step_type = relationship("RStepType") def __str__(self): info={ 'ID_STEP':self.ID_STEP, 'ID_TRANSFORMATION':self.ID_TRANSFORMATION, 'NAME':self.NAME, 'DESCRIPTION':self.DESCRIPTION, 'ID_STEP_TYPE':self.ID_STEP_TYPE, 'DISTRIBUTE':self.DISTRIBUTE, 'COPIES':self.COPIES, 'GUI_LOCATION_X':self.GUI_LOCATION_X, 'GUI_LOCATION_Y':self.GUI_LOCATION_Y, 'GUI_DRAW':self.GUI_DRAW, 'COPIES_STRING':self.COPIES_STRING, } info.update(self.r_step_type.toDict()) return json.dumps(info) def toDict(self): info={ 'ID_STEP':self.ID_STEP, 'ID_TRANSFORMATION':self.ID_TRANSFORMATION, 'NAME':self.NAME, 'DESCRIPTION':self.DESCRIPTION, 'ID_STEP_TYPE':self.ID_STEP_TYPE, 'DISTRIBUTE':self.DISTRIBUTE, 'COPIES':self.COPIES, 'GUI_LOCATION_X':self.GUI_LOCATION_X, 'GUI_LOCATION_Y':self.GUI_LOCATION_Y, 'GUI_DRAW':self.GUI_DRAW, 'COPIES_STRING':self.COPIES_STRING, } info.update(self.r_step_type.toDict()) return info ``` 直接使用： ```python step = session.query(entity.RStep).filter(entity.RStep.ID_TRANSFORMATION == ID_TRANSFORMATION).order_by(entity.RStep.ID_STEP.asc()) data = step.frist() print(data) ```
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