python - How to get all related/parent instances from set of child instances without looping through latter set -

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कृपया निम्नलिखित Django मॉडलों का ध्यान रखें: 

  ParentModel (models.Model): .. बच्चे मॉडल (मॉडेल। मॉडल): माता पिता = मॉडल। विदेशी (पैरेन्टमोडेल, संबंधित_नाम = 'बच्चों')

मान लीजिए कि क्वेरी के रूप में उपलब्ध डेटाबेस में सभी बच्चों का कुछ सबसेट है ( इसे 1 सेट पर कॉल करें)।
अब, मैं सभी माता-पिता के सबसेट तक पहुंच हासिल करना चाहता हूं (इसे दूसरे सेट पर कॉल करें), जिसमें कहा गया है कि 1 सेट से बच्चे संबंधित हैं।

कैसे क्या आप ऐसा करते हैं कि पायथन स्तर (और संभवत: डीबी हिट की एक रैखिक संख्या के कारण) पर 1 सेट के बिना पाशन, यानी केवल एक या दो डीबी हिट के साथ?

धन्यवाद!

मान लें कि आपके पास बच्चों नामक एक क्वेरी है: 

  ParenModel.objects.filter (children__in = बच्चे)

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