Yangi model qoshing xuddi Score model kabi

Certificate modeli quyidagicha bo‘ladi:

Field	Type	Izoh
student_id	FK → Student	Sertifikat kimga berilgan
title	String	Sertifikat nomi
content	Text/String	Sertifikat mazmuni yoki description
issued_at	DateTime	Berilgan vaqt (default = now)
certificate_code	String unique	Unikal sertifikat kodi
is_verified	Boolean	Tekshirilgan/yo‘q

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🟩 Student modeliga qo‘shish

# Student modeli ichida
certificates = relationship('Certificate', back_populates='student')

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🟧 Uyga vazifa — Certificate bilan practice

1. Insert

1. Student 1 uchun yangi certificate qo‘sh: title="Python Basics", content="Completed course", certificate_code random orqali yarating
2. Student 2 uchun 2 ta certificate qo‘sh

2. Query

3. Barcha certificate larni oling
4. is_verified=False bo‘lgan certificate lar
5. Berilgan student_id uchun barcha certificate lar
6. certificate_code bo‘yicha certificate qidirish
7. issued_at bo‘yicha 5 ta oxirgi certificate

3. Update

8. certificate_code bo‘yicha is_verified=True qil

5. Aggregation

9. Studentlar bo‘yicha certificate soni
10. Eng ko‘p certificate olgan student
11. is_verified bo‘lgan certificate larni count qilish