在Django 1.9中加入多個表格

Question

我仍在學習Django。任何熟悉Django 1.8或更高版本的人都可以幫助我解決這個問題。我在參加這5臺的問題，我想執行一個查詢，相當於這個SQL查詢：

SELECT * 
from modelname1 a 
join modelname2 b on a.id = b.id 
join modelname3 c on c.id = b.id 
join modelname4 d on d.id = c.id 
join modelname5 on e.id = d.id; 

我有這些模型：

class modelname1(models.Model): 
    modelname1_id = models.AutoField(primary_key = True) 
    a = models.CharField(max_length = 200) 
    b = models.CharField(max_length = 200) 

class modelname2(models.Model): 
    modelname2_id = models.AutoField(primary_key = True) 
    a = models.CharField(max_length = 200) 
    b = models.CharField(max_length = 200) 
    c = models.ForeignKey(modelname1) 

class modelname3(models.Model): 
    modelname3_id = models.AutoField(primary_key = True) 
    a = models.CharField(max_length = 200) 
    b = models.CharField(max_length = 200) 
    c = models.ForeignKey(modelname2) 

class modelname4(models.Model): 
    modelname4_id = models.AutoField(primary_key = True) 
    a = models.CharField(max_length = 200) 
    b = models.CharField(max_length = 200) 
    c = models.ForeignKey(modelname3) 

class modelname5(models.Model): 
    modelname5_id = models.AutoField(primary_key = True) 
    a = models.CharField(max_length = 200) 
    b = models.CharField(max_length = 200) 
    c = models.ForeignKey(modelname4) 

我不知道怎麼翻譯我想在Django上面的查詢， 我可以使查詢得到相同的答案，但我需要將它分成多個查詢之前得到相同的答案。 非常感謝您的幫助！

Answer 1

在Django中你可以簡單的查詢是這樣的：

>>>from app.models import modelname1 
>>> q = modelname1.objects.get(id = 1) 
>>> m2 = q.modelname2 # In django 1.8 or later 
>>> m3 = m2.modelname3 
>>> m4 = m3.modelname4 
... And so on! 

但我不提供，因爲很多數據庫擊球的這種方式。如果你想優化你的數據庫訪問可以閱讀這篇文章： https://docs.djangoproject.com/en/1.9/topics/db/optimization/