sqlalchemy orm列名约定

在将控件传递给 DeclarativeMeta . 另一种方法是在 before_parent_attach 的事件处理程序 Column ,但与使用特定声明性基的映射类中的列相比,这将全局影响所有列。

from sqlalchemy.ext.declarative.api import DeclarativeMeta
from sqlalchemy import Column

class RenamingDeclarativeMeta(DeclarativeMeta):
    def __init__(cls, name, bases, namespace):
        _rename_declared_columns(namespace)
        super().__init__(name, bases, namespace)

    def __setattr__(cls, key, value):
        if isinstance(value, Column):
            _undefer_column_name_only(key, value)
        super().__setattr__(key, value)

def to_camelcase(s):
    return ''.join([w.title() for w in s.split('_')])

def _undefer_column_name_only(key, column):
    if column.name is None:
        column.name = to_camelcase(key)

def _rename_declared_columns(namespace):
    for key, attr in namespace.items():
        if isinstance(attr, Column):
            _undefer_column_name_only(key, attr)

ColumnProperty 和 CompositeProperty metaclass 到 declarative_base() :

In [2]: from sqlalchemy.ext.declarative import declarative_base

In [3]: Base = declarative_base(metaclass=RenamingDeclarativeMeta)

In [4]: from sqlalchemy import Column, Integer

In [5]: class Foo(Base):
   ...:     __tablename__ = 'foo'
   ...:     id = Column(Integer, primary_key=True)
   ...:     bar_baz_1 = Column(Integer, nullable=False)
   ...:     

In [6]: Foo.id
Out[6]: <sqlalchemy.orm.attributes.InstrumentedAttribute at 0x7ffb7f770e60>

In [7]: Foo.bar_baz_1
Out[7]: <sqlalchemy.orm.attributes.InstrumentedAttribute at 0x7ffb7dc47200>

In [8]: list(Foo.__table__.columns)
Out[8]: 
[Column('Id', Integer(), table=<foo>, key='id', primary_key=True, nullable=False),
 Column('BarBaz1', Integer(), table=<foo>, key='bar_baz_1', nullable=False)]

另一种方法是全局重命名附加到的所有列 Table 对象使用 event API

from sqlalchemy import event

@event.listens_for(Column, 'before_parent_attach')
def receive_column_before_table_attach(column, table):
    # As dumb as it gets. Blindly modifies all columns.
    column.name = to_camelcase(column.name)

这个有一个 专业