SQL Alchemy 枚举验证与验证函数冲突

Question

我正在尝试使用 sqlalchemy enum 类型而不创建本机 DB ENUM 列，但仍然让 sqlalchemy 验证枚举输入。

所以我有这个声明：

from sqlalchemy import Column
from sqlalchemy import Integer
from sqlalchemy import Enum as SaEnum
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy.orm import validates
import enum

Base = declarative_base()

class DummyEnum(enum.Enum):
    NAME_1 = "NAME_1"
    NAME_2 = "NAME_2"

class SAEnumVarcharTable(Base):
    __tablename__ = "test_table"
    id = Column(Integer, primary_key=True)
    uut_column = Column(SaEnum(DummyEnum, native_enum=False, validate_strings=True), default=DummyEnum.NAME_1)

    @validates('uut_column')
    def validate_uut_column(self, key, uut_value):
        return uut_value.upper()

我想要验证 return 大写字符串，然后才进行枚举验证... 可能吗？

因为当我这样做时 :

connection.execute(insert(SAEnumVarcharTable), {"uut_column" : "name_1"})

它确实引发了一个 LookupError 我希望被接受为有效输入的地方（首先进入验证函数 -> return 一个大写字符串 -> 进行枚举验证）。 .有可能吗？

Answer 1

验证器仅在修改实例的属性时调用，例如：

instance = SAEnumVarcharTable()
instance.uut_column = "name_1"

在您的情况下，您需要覆盖 sqlalchemy.Enum 的 _db_value_for_elem:

class UpperCaseEnum(SaEnum):

    def _db_value_for_elem(self, elem):
        return super()._db_value_for_elem(elem.upper())

# uut_column = Column(SaEnum(...), ...)
uut_column = Column(UpperCaseEnum(...), ...)

放在一边

验证器实现

validate_uut_column 未正确实施。

instance = SAEnumVarcharTable()
instance.uut_column = "name_0"  # No error, expected LookupError

instance.uut_column = "name_1"  # Ok
print(instance.uut_column == DummyEnum.NAME_1)  # False, expected True
print(instance.uut_column.value == "NAME_1")    # AttributeError: 'str' object has no attribute 'value'

instance.uut_column = DummyEnum.NAME_1  # AttributeError: 'DummyEnum' object has no attribute 'upper'

相反，它应该是：

@validates('uut_column')
def validate_uut_column(self, key, uut_value):
    # return uut_value.upper()
    return uut_value if uut_value in DummyEnum else DummyEnum[uut_value.upper()]

instance = SAEnumVarcharTable()
instance.uut_column = "name_0"  # LookupError, as expected

instance.uut_column = "name_1"  # Ok
print(instance.uut_column == DummyEnum.NAME_1)  # True, as expected
print(instance.uut_column.value == "NAME_1")    # True, as expected

instance.validate_uut_column = DummyEnum.NAME_1  # Ok

SQL Alchemy 枚举验证与验证函数冲突

SQL Alchemy enum validation conflict with validate function

orm

enums

sqlalchemy

python-3.x

放在一边

验证器实现