# models.py

class Boy(models.Model):
  name = models.CharField(max_length=32)

class Girl(models.Model):
  name = models.CharField(max_length=32)


class Love(models.Model):
  b = models.ForeignKey('Boy')
  g = models.ForeignKey('Girl')

  # 創(chuàng)建聯(lián)合唯一索引
  # class Meta:
  #   unique_together = [
  #     ('b','g')，
  #   ]




# views.py

def test(request):
  # objs = [
  #   models.Boy(name='summer'),
  #   models.Boy(name='spring'),
  #   models.Boy(name='autumn'),
  # ]
  # models.Boy.objects.bulk_create(objs,5)

  # objs = [
  #   models.Girl(name='小于'),
  #   models.Girl(name='小秋'),
  #   models.Girl(name='小夏'),
  # ]
  # models.Girl.objects.bulk_create(objs,5)

# 查詢和girl小于有關(guān)系的boy

# 1 通過girl表進(jìn)行反向查找
  obj = models.Girl.objects.filter(name='小于').first().love_set.all()
  # obj = models.Girl.objects.filter(name='小于').first().love_set.select_related('b').all()
  for i in obj:
    print(i.b.name)




  print(' '.center(60,'='))



# 2 通過Love表進(jìn)行查找

  obj = models.Love.objects.filter(g__name='小于').all()
  for i in obj:
    print(i.b.name)

  # 這樣進(jìn)行查詢性能不好，需要重新發(fā)sql請求在進(jìn)行查詢另外一張表中的數(shù)據(jù)

  boy_list = models.Love.objects.filter(g__name='小于').values('b__name')
  for i in boy_list:
    print(i['b__name'])

  # 這樣 進(jìn)行了 優(yōu)化 不會重復(fù)發(fā)送sql請求，查詢到的結(jié)果內(nèi)是字典

  boy_obj = models.Love.objects.filter(g__name='小于').select_related('b').all()
  for i in boy_obj:
    print(i.b.name)
  # select_related('ut') 相當(dāng) 于 inner join 先連成一張表再進(jìn)行查詢

  return HttpResponse('insert ok ....')

# models.py
from django.db import models

class Boy(models.Model):
  name = models.CharField(max_length=32)
  # m = models.ManyToManyField('Girl')

class Girl(models.Model):
  name = models.CharField(max_length=32)
  m = models.ManyToManyField('Boy')

# views.py

def test(request):
  # objs = [
  #   models.Boy(name='summer'),
  #   models.Boy(name='spring'),
  #   models.Boy(name='autumn'),
  # ]
  # models.Boy.objects.bulk_create(objs,5)

  # objs = [
  #   models.Girl(name='小于'),
  #   models.Girl(name='小秋'),
  #   models.Girl(name='小夏'),
  # ]
  # models.Girl.objects.bulk_create(objs,5)


  # ManyToManyField

  obj = models.Girl.objects.filter(name='小秋').first()

  # 增
  # obj.m.add(3)
  # obj.m.add(3,4)
  # obj.m.add(*[1,2])

  # 刪
  # obj.m.remove(3)
  # obj.m.remove(3,4)
  # obj.m.remove(*[1,2])

  # 改
  # obj.m.set([1,2,])

  # boy_obj = obj.m.all()
  # for row in boy_obj:
  #   print(row.id,row.name)
  # 清除
  # obj.m.clear()


  # 反向查 在沒有 ManyToManyField 字段的表中查
  obj = models.Boy.objects.filter(name='summer').first()
  girl_obj = obj.girl_set.all()
  # 增刪改查
  obj.girl_set.set([1,2,3])

  for row in girl_list:
    print(row.id,row.name)

  return HttpResponse('ok')

# modles.py
class Boy(models.Model):
  name = models.CharField(max_length=32)

class Girl(models.Model):
  name = models.CharField(max_length=32)
  m = models.ManyToManyField('Boy',through='Love',through_fields=('b','g')) # 只讓其生成3張表，如果不加后面產(chǎn)生生成4張表

class Love(models.Model):
  b = models.ForeignKey('Boy')
  g = models.ForeignKey('Girl')

# views.py
def test(request):
  obj = models.Girl.objects.filter(name='小于').first()
  # obj.m.add(1) # 不行
  # obj.m.remove(1) # 不行
  # obj.m.set([1,2]) # 不行
  # obj.m.clear() # 可以
  # obj.m.all() # 可以

  # 雜交的方法對獲取查詢方便點(diǎn)，還添加了清空功能

  boy_obj = obj.m.all()

  for i in boy_obj:
    print(i.name)