Porting (postgresql) SQL into django model classes - django

Question

I am porting a database schema (by hand), from (postgresql) SQL to django (1.10) model.
Here is my SQL:
CREATE TABLE ref_continent (
id SERIAL PRIMARY KEY,
name VARCHAR(64)
);
CREATE UNIQUE INDEX idxu_continent_nm ON ref_continent (name);
CREATE TABLE ref_geographic_region (
id SERIAL PRIMARY KEY,
continent_id INTEGER REFERENCES ref_continent(id) ON DELETE RESTRICT ON UPDATE CASCADE,
name VARCHAR(256)
);
CREATE UNIQUE INDEX idxu_geogreg_nm ON ref_geographic_region (name);
I am particularly interested in how to create the UNIQUE INDEX and how to link the FK to the PKey, since (AFAIK), django creates the primary key id behind the scenes?

Answer 1

According to docs
Note that when unique is True, you don’t need to specify db_index,
because unique implies the creation of an index.
Well, when you link a model as a foreign key, it links to default FK(that's id by default).
models.ForeignKey('app_name.ref_continent', )
there is another class class META that is used to fix these things. You don't have to almost ever specify to link FK to PK of other table, this is all done by Django. Have a at source code
models.py
class ref_continent(models.Model):
# Fields
name = models.CharField(max_length=64,unique=True)#making unique=True will generate query that will have UNIQUE INDEX both in PLSQL
def __unicode__(self):
return u'%s' % self.pk
class ref_geographic_region(models.Model):
# Fields
name = models.CharField(max_length=64,unique=True)
# Relationship Fields
continent_id = models.ForeignKey('app_name.ref_continent', )
def __unicode__(self):
return u'%s' % self.pk