Adding Foreign Keys in Database Tables of Django Application

To make an attribute foreign in another table, it has to be made primary in its home table.

Lets take an example of two tables named "primary" and "foreign".

class primary(models.Model):

       name = models.CharField(max_length = 30)

       id = models.CharField(max_length = 30, primary_key = True)

here in the "primary table" , id should be made primary key to be used as foreign key in secondary table.

class secondary(models.Model):

         dob = models.CharField(max_length = 30)

         id = models.ForeignKey(primary)

here,the "id" in the table named "secondary" has been made foreign key by using ForeignKey()  field with name of the parent table of the attribute "id" inserted as its parameter to make "id" as the foreign key in the
table named "secondary".