Question

我想在数据库中关联两个表。我为此项目使用sqlalchemy和mariadb。

当表描述中的列描述设置为String且最大值为700时，效果很好。

class Edition(Base):
    __tablename__= "edition"

    idEdition = Column(Integer, primary_key=True)
    description = relationship("Description", back_populates="edition")

class Description(Base):
    __tablename__ = "description"

    idDescription = Column(Integer, primary_key=True)
    edition_id = Column(Integer, ForeignKey('edition.idEdition'), nullable=False)
    description = Column(String(700), nullable=False)
    edition = relationship("Edition", back_populates="description")
    UniqueConstraint(edition_id, description)

但是我需要存储更长的描述。如果我尝试description = Column(String(800), nullable=False) 有错误：

sqlalchemy.exc.DatabaseError: (mysql.connector.errors.DatabaseError) 1005 (HY000): Can't create table `bestsellers`.`description` (errno: 150 "Foreign key constraint is incorrectly formed")

与description = Column(LONGTEXT, nullable=False)

相同

我认为类型有问题，但目前无法找到...

编辑根据Gord Thompson的建议，我更改了Description类：

class Description(Base):
    __tablename__ = "description"

    idDescription = Column(Integer, primary_key=True)
    edition_id = Column(Integer, ForeignKey('edition.idEdition'), nullable=False)
    description = Column(LONGTEXT, nullable=False)
    description_short = Column(String(750), nullable=False)
    edition = relationship("Edition", back_populates="description")
    UniqueConstraint(edition_id, description_short)

，它似乎正在工作。但是，我不知道mysql：

CREATE TABLE description (idDescription INTEGER NOT NULL AUTO_INCREMENT,

edition_id INTEGER NOT NULL, description LONGTEXT NOT NULL, PRIMARY KEY 

(`idDescription`), UNIQUE (edition_id, description(750)), FOREIGN KEY(edition_id) 

REFERENCES edition (`idEdition`));

可以直接翻译成python sqlalchemy吗？我宁愿不添加新列。出于UniqueConstraint的目的，仅限制现有列会很好。

1005（HY000）：无法创建表

0 个答案: