model methods returning empty strings-CodePudding

I am getting empty in return (from my model methods), I don't get where I am wrong in this, we can query model using self

class SocialLinks(models.Model):
    alias_name = models.CharField(max_length=10,)
    name = models.CharField(max_length=30)
    url_link = models.URLField()


    def get_fb_link(self):
        try:
            fb = self.objects.get(alias_name='fb')
            return fb.url_link 
        except:
            return ""
    
    def get_linkdin_link(self):
        try:
            linkdin = self.objects.get(alias_name='linkedin')
            return linkdin 
        except:
            return ""

    def get_insta_link(self):
        try:
            insta = self.objects.get(alias_name='insta')
            return insta.url_link 
        except:

CodePudding user response：

Your issue is that self corresponds to one instance of the model class, not the class itself.

So you can do

all_fb_links = SocialLinks.objects.filter(alias_name="fb")

and you will get all the records from the model that are facebook links, but you cannot do this referencing a single instance of the record using self.

You could write a class method, but what you actually want here is a model manager to define some specific queries so that you can then do

SocialLinks.get_all_fb_links()

Here's the docs on defining a custom manager: https://docs.djangoproject.com/en/3.2/topics/db/managers/

A method on the class like you are defining would be used to return something not stored on the table, but which could perhaps be derived from it. A simple example might be:

def link_type_and_url(self):
   return f"{self.alias_name}:{url_link}"