DRF PUT request on unique model field - django

Question

I have the following model:
class Movie(models.Model):
name = models.CharField(max_length=800, unique=True)
imdb_rating = models.IntegerField(null=True)
movie_choice = (
('Act', 'Action'),
...........
)
movie_type = models.CharField(max_length=3, choices=movie_choice)
created_at = models.DateTimeField(auto_now_add=True)
updated_at = models.DateTimeField(auto_now=True)
class Hiren(models.Model):
movie = models.ForeignKey(Movie)
watched_full = models.BooleanField(default=True)
rating = models.IntegerField()
source = models.CharField(max_length=500, null=True)
watched_at = models.DateField()
quality_choice = (
..................
)
video_quality = models.CharField(max_length=3, choices=quality_choice)
created_at = models.DateField(auto_now_add=True)
updated_at = models.DateField(auto_now=True)
and serializer:
class MovieSerializer(serializers.ModelSerializer):
class Meta:
model = Movie
fields = '__all__'
class HirenSerializer(serializers.ModelSerializer):
movie = MovieSerializer()
class Meta:
model = Hiren
fields = ('movie', 'id', 'watched_full', 'rating', 'source', 'video_quality', 'watched_at')
def update(self, instance, validated_data):
instance.movie.name = validated_data.get('movie', {}).get('name')
instance.movie.imdb_rating = validated_data.get('movie', {}).get('imdb_rating')
instance.movie.movie_type = validated_data.get('movie', {}).get('movie_type')
instance.watched_full = validated_data.get('watched_full', instance.watched_full)
instance.rating = validated_data.get('rating', instance.rating)
instance.source = validated_data.get('source', instance.source)
instance.video_quality = validated_data.get('video_quality', instance.video_quality)
instance.watched_at = validated_data.get('watched_at', instance.watched_at)
instance.movie.save()
instance.save()
return instance
When I try to send a put request without changing name field from Movie model it throws an error
{
"movie": {
"name": [
"movie with this name already exists."
]
}
}
However, I can perfectly update any other field if I change the name field's value each time.

Answer 1

The problem is in Movie model defined by you.
When you set the name field of Movie model as unique = True,then any new entry with same movie name will always throw an error.
In your model,
class Movie(models.Model):
name = models.CharField(max_length=800, unique=True)
imdb_rating = models.IntegerField(null=True)
movie_choice = (
('Act', 'Action'),
...........
)
movie_type = models.CharField(max_length=3, choices=movie_choice)
created_at = models.DateTimeField(auto_now_add=True)
updated_at = models.DateTimeField(auto_now=True)
If you want to add two entries with the same name,remove the line unique = True or make sure to save every entry with a different name.
Or,if you want to update the record/entry then you don't need to assign a value for name field,just remove that line from your code,alternatively check if the name of the movie is already same with an improvement in the code like this :
class HirenSerializer(serializers.ModelSerializer):
movie = MovieSerializer()
class Meta:
model = Hiren
fields = ('movie', 'id', 'watched_full', 'rating', 'source', 'video_quality', 'watched_at')
def update(self, instance, validated_data):
movie_name = validated_data.get('movie', {}).get('name')
if movie_name != instance.movie.name :
instance.movie.name = movie_name
instance.movie.imdb_rating = validated_data.get('movie', {}).get('imdb_rating')
instance.movie.movie_type = validated_data.get('movie', {}).get('movie_type')
instance.watched_full = validated_data.get('watched_full', instance.watched_full)
instance.rating = validated_data.get('rating', instance.rating)
instance.source = validated_data.get('source', instance.source)
instance.video_quality = validated_data.get('video_quality', instance.video_quality)
instance.watched_at = validated_data.get('watched_at', instance.watched_at)
instance.save()
return instance
Hope this helps,Thanks.