from django.db import models

​

class ExampleModel(models.Model):

    field1 = models.CharField(max_length=100)

    field2 = models.CharField(max_length=100)

​

    class Meta:

        constraints = [

            models.UniqueConstraint(fields=['field1', 'field2'], name='unique_field1_field2')

​

# The <name> argument provides a clear identifier for the constraint in the database.

static void Main(string[] args)

    {

        string s1 = "i have a car a car";

        string s2 = "i have a new car bmw";

​

        List<string> diff;

        IEnumerable<string> set1 = s1.Split(' ').Distinct();

        IEnumerable<string> set2 = s2.Split(' ').Distinct();

​

        if (set2.Count() > set1.Count())

        {

            diff = set2.Except(set1).ToList();

        }

        else

        {

            diff = set1.Except(set2).ToList();

        }

    }