python - 将 sql 查询初始化为数据类

Question

目标是根据字段的一些手动分类实现SQL中的选定列，例如

from dataclasses import dataclass


@dataclass
class Q:
    fruits = ('taste', 'color', 'shine')
    vege = ('is_green', 'color', 'juiceable')
    meat = ('is_white', 'is_dark', 'is_red', 'meat_name')
    carbs = ('is_refined', 'gi')

    @static_method
    def get_fields(self, add_fruits=False, add_vege=False, add_meat=False, add_carbs=False):
         fields = set()
         fields.update(self.fruits) if add_fruits else None
         fields.update(self.vege) if add_vege else None
         fields.update(self.meat) if add_meat else None
         fields.update(self.carbs) if add_carbs else None
         return sorted(",".join(sorted(fields)))


print(f"SELECT {Q.get_fields(add_fruits=True, add_vege=True)} from food_features")

给定 Q 对象中的大量字段类别列表，我们如何避免在 .get_fields 函数中进行硬编码？

fields.update(self._field_name_) if add_field_name else None 

Answer 1

这是您正在寻找的输出/功能吗？

class Q :
    def __init__(self):
        self.categories = {
            'fruits': ('taste', 'color', 'shine'),
            'vege': ('is_green', 'color', 'juiceable'),
            'meat': ('is_white', 'is_dark', 'is_red', 'meat_name'),
            'carbs': ('is_refined', 'gi')
        }
    
    def get_fields(self, groups):
        fields = []
        for group in groups:
            fields.extend(self.categories[group])
        return", ".join(sorted(set(fields)))

value = Q()
print(f"SELECT {value.get_fields(['fruits', 'vege'])} FROM food_features")

输出:

SELECT color, is_green, juiceable, shine, taste FROM food_features