详解Django中ORM查询的改进方案与说明

try:
    instance = mc_groupcustomerlkwist.objects.get(filenamemark=filenamemark)
    return instance.toJson()
except mc_groupcustomerlkwist.DoesNotExist:
    return JsonResponse({'error': '未找到记录'}, status=404)
except mc_groupcustomerlkwist.MultipleObjectsReturned:
    return JsonResponse({'error': '存在重复记录'}, status=500)

from django.core import serializers

instance = mc_groupcustomerlkwist.objects.only(
    'id', 'name', 'create_time'
).filter(filenamemark=filenamemark).first()

if instance:
    return serializers.serialize('json', [instance], fields=('id', 'name'))
return None

from django.http import JsonResponse
from django.core.cache import cache
from rest_framework import serializers

class CustomerSerializer(serializers.ModelSerializer):
    class Meta:
        model = mc_groupcustomerlkwist
        fields = '__all__'
        read_only_fields = ('create_time',)

def get_customer_data(filenamemark):
    cache_key = f"customer_{filenamemark}"
    if cached := cache.get(cache_key):
        return cached
        
    try:
        instance = mc_groupcustomerlkwist.objects.select_related('group').get(
            filenamemark=filenamemark
        )
        data = CustomerSerializer(instance).data
        cache.set(cache_key, data, timeout=300)
        return data
    except mc_groupcustomerlkwist.DoesNotExist:
        logger.warning(f"未找到filenamemark={filenamemark}的记录")
        return None

class mc_groupcustomerlkwist(models.Model):
    filenamemark = models.CharField(max_length=100, db_index=True)

from channels.db import database_sync_to_async

@database_sync_to_async
def async_get_customer(filenamemark):
    return get_customer_data(filenamemark)