英文:
Get value of a field from a foreigKey in Django Models
问题
现在，我有两个在我的Django数据库中的类：
class Test(models.Model):
sequenzaTest = models.ForeignKey("SequenzaMovimento", null=True, on_delete=models.SET_NULL)
class SequenzaMovimento(models.Model):
nomeSequenza = models.CharField(max_length=50, blank=False, null=False)
serieDiMovimenti = models.TextField(blank=False, null=False, default="")
现在，每个Test对象都可以关联到一个SequenzaMovimento对象。不同的Test对象可以关联到相同的SequenzaMovimento对象。
现在，我知道我的Test对象的主键。如何找到与Test对象关联的SequenzaMovimento对象中的serieDiMovimenti？
我可以从Test对象中获取sequenzaTest：
testo_sequenza = Test.objects.get(pk=idObj)
testo_sequenza.sequenzaTest
但是我不知道如何访问serieDiMovimenti。
英文:
I have two classes in my Database in Django
class Test(models.Model):
sequenzaTest = models.ForeignKey("SequenzaMovimento", null=True, on_delete=models.SET_NULL)
class SequenzaMovimento(models.Model):
nomeSequenza = models.CharField(max_length=50, blank=False, null=False)
serieDiMovimenti = models.TextField(blank=False, null=False, default="")
Now, every Test object created can be associated with just one SequenzaMovimento object. Different Test objects can have the same SequenzaMovimento
Now, I know the primary key of my Test. How do I find the serieDiMovimenti inside the SequenzaMovimento object which is linked to the Test object?
I can get the sequenzaTest from the Test object with
testo_sequenza = Test.objects.get(pk=idObj)
testo_sequenza.sequenzaTest
but I can't find to understand how access serieDiMovimenti
答案1
得分: 1
testo_sequenza = Test.objects.get(pk=idObj)
testo_sequenza.sequenzaTest.serieDiMovimenti
英文:
You could try:
testo_sequenza = Test.objects.get(pk=idObj)
testo_sequenza.sequenzaTest.serieDiMovimenti
答案2
得分: 1
这应该可以工作：
try:
testo_sequenza = Test.objects.get(pk=idObj)
except Test.DoesNotExist:
# 如果未找到，可以在这里执行程序需要执行的操作。如果在循环中，可以考虑使用 return 或 continue/break
print("Testo Sequenza not found")
sequenza_test = testo_sequenza.sequenzaTest
serie_di_movimenti = sequenza_test.serieDiMovimenti
此外，您还应该检查以下代码：
serieDiMovimenti = models.TextField(blank=False, null=False, default="")
因为如果您希望它是一个"可选字段"，那么应该是 blank=True。
英文:
This should work:
try:
testo_sequenza = Test.objects.get(pk=idObj)
except Test.DoesNotExist:
# do here what you need the program to do if not found. maybe a return if function or a continue/break if you're in a loop
print("Testo Sequenza not found")
sequenza_test = testo_sequenza.sequenzaTest
serie_di_movimenti = sequenza_test.serieDiMovimenti
Also you should check
serieDiMovimenti = models.TextField(blank=False, null=False, default="")
Because if you want it to be "optional field" then it would be blank=True
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