如何声明包含多列主键的表类? [英] How to declare a table class that contains multi-column primary key?

问题描述

主键的列必须按特定顺序排列.

The columns of the primary key must be in specific order.

我从文档中看到一些代码:

I see some code from document :

class User(Base):
    __tablename__ = 'users'

    id = Column(Integer)

    __mapper_args__ = {
        'primary_key':[id]
    }

但是就是不行(我用的是mysql，不会生成id主键).任何可能的解决方案?

But it just does not work (I'm using mysql, and the id primary key will not be generated). Any possible solutions?

推荐答案

如果列的声明顺序与它们在主键中的顺序相同:

In case columns are declared in the same order as they should be in the primary key:

class User(Base):
    field1 = Column(Integer, primary_key=True)
    field2 = Column(Integer, primary_key=True)

否则在__table_args__中声明:

class User(Base):
    field1 = Column(Integer)
    field2 = Column(Integer)
    __table_args__ = (
        PrimaryKeyConstraint(field2, field1),
        {},
    )

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