简单生成SQL语句的ORM

SQL语句ORM

class ModelMetaclass(type):
    def __new__(cls, name, bases, attrs):
        mappings = dict()
        for k, v in attrs.items():
            if isinstance(v, tuple):
                mappings[k] = v

        for k in mappings.keys():
            attrs.pop(k)

        attrs['__mappings__'] = mappings
        attrs['__table__'] = name
        return type.__new__(cls, name, bases, attrs)


class User(metaclass=ModelMetaclass):
    uid = ('uid', "int unsigned")
    name = ('username', "varchar(30)")
    email = ('email', "varchar(30)")
    password = ('password', "varchar(30)")

    def __init__(self, **kwargs):

        for name, value in kwargs.items():
            setattr(self, name, value)

    def save(self):
        fields = []
        args = []
        for k, v in self.__mappings__.items():
            fields.append(v[0])
            args.append(getattr(self, k, None))

        sql = 'insert into %s (%s) values (%s)' % (self.__table__, ','.join(fields), ','.join([str(i) for i in args]))
        print('SQL: %s' % sql)


u = User(uid=12345, name='Michael', email='[email protected]', password='my-pwd')
u.save()