How to select the proper column when I use ForeignKey?

[Kubilay Yazoğlu]

Hello. I have two models. In one of them, I declared a foreign key to the other one. Since this is done in Django by only specifying the Class name, without specifying the field name(column name), when I try to create an object in admin panel, it pulls the wrong column information.

Two models A and B.

B has a Foreignkey for accessing A.

A has two fields Field1 and Field2.

When I try to create an instance of B, in the field of Foreignkey, there is a drop down menu but the content is not from the right field of A.

How to specify it?

[Matemática A3K]

What Django shows in that dropdown is the __str__() method of the object, define it to your needs in A :)

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[Kubilay Yazoğlu]

Thanks for your answer. I have one more question. What if there are more than one primary keys in that table? I'm talking about the unique_together case.

27 Kasım 2017 Pazartesi 08:55:45 UTC+3 tarihinde Matemática A3K yazdı:

What Django shows in that dropdown is the __str__() method of the object, define it to your needs in A :)

On Sun, Nov 26, 2017 at 7:49 PM, Kubilay Yazoğlu <kyaz...@gmail.com> wrote:

Hello. I have two models. In one of them, I declared a foreign key to the other one. Since this is done in Django by only specifying the Class name, without specifying the field name(column name), when I try to create an object in admin panel, it pulls the wrong column information.

Two models A and B.

B has a Foreignkey for accessing A.

A has two fields Field1 and Field2.

When I try to create an instance of B, in the field of Foreignkey, there is a drop down menu but the content is not from the right field of A.

How to specify it?

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To unsubscribe from this group and stop receiving emails from it, send an email to django-users...@googlegroups.com.

[Matemática A3K]

On Mon, Nov 27, 2017 at 10:50 AM, Kubilay Yazoğlu <kyaz...@gmail.com> wrote:

Thanks for your answer. I have one more question. What if there are more than one primary keys in that table?

By definition, that won't happen, a primary key is unique. If you add a record with the same key Django will raise an IntegrityError.

 

I'm talking about the unique_together case.

I don't understand you

 

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[Matemática A3K]

On Mon, Nov 27, 2017 at 5:30 PM, Matemática A3K <matemat...@gmail.com> wrote:

On Mon, Nov 27, 2017 at 10:50 AM, Kubilay Yazoğlu <kyaz...@gmail.com> wrote:

Thanks for your answer. I have one more question. What if there are more than one primary keys in that table?

By definition, that won't happen, a primary key is unique. If you add a record with the same key Django will raise an IntegrityError.

 

I'm talking about the unique_together case.

I don't understand you

The ForeignKey uses the model's auto primary key to "link", if you define other keys, np. You should read https://docs.djangoproject.com/en/1.11/ref/models/fields/#foreignkey

The __str__() representation of the object is independent of the keys you define on it. If you want to tweak what is displayed in the drop-down, use this method to show whatever you need :)

[Kubilay Yazoğlu]

Thanks. I was talking about the composite primary keys in my second question. I've seen that there is a library for it. So, no problem now. Thank you.

27 Kasım 2017 Pazartesi 23:31:29 UTC+3 tarihinde Matemática A3K yazdı: