If an app has multiple models with the same field, whats the best practice for keeping things DRY?

For example, if I have 3 models that look like this:

class CallLog(models.Model):
    lead_id = models.BigIntegerField("Lead ID")
    #  other fields


class EmailLog(models.Model):
    lead_id = models.BigIntegerField("Lead ID")
    #  other fields


class TextLog(models.Model):
    lead_id = models.BigIntegerField("Lead ID")
    #  other fields

Do I add lead_id to each model individually or is there a way to only type it once?

>Solution :

Yes, you can define an abstract base class ^[Django-doc]:

class LeadIdModel(models.Model):
    lead_id = models.BigIntegerField("Lead ID")

    class Meta:
        abstract = True

and then inherit this in the other models:

class CallLog(LeadIdModel, models.Model):
    # other fields…


class EmailLog(LeadIdModel, models.Model):
    # other fields…


class TextLog(LeadIdModel, models.Model):
    # other fields…

You can define multiple such abstract base classes, and use multiple inheritance such that models inherit from multiple of such classes.