[FIXED] CqlEngine model primary_key not raising Unique Error

Issue

I am using CassandraDB in a flask project

I have created a User Model which has email as the primary_key.

class User(Model):
    __table_name__ = 'user'

    user_id = UUID(primary_key=True)
    email = Text(max_length=120, primary_key=True)
    first_name = Text()
    last_name = Text()

python code:

user_data = {'email': '[email protected]', "first_name":'John', "last_name":'Doe'}
user = User(**user_data)
user.save()

the Above code correctly creates the user as required

user_data = {'email': '[email protected]', "first_name":'Johnny', "last_name":'Daves'}
user = User(**user_data)
user.save()

Now the above code updates the existing User 'john doe' to 'johnny daves'. what I was expecting to get was an error raised by cqlengine stating "user with email [email protected] already exists"

Why did it not raise the error? Am I doing something wrong?

Solution

I manage to figure out the answer, after going through the code I was able to notice that Model class has an property called _if_not_exists = False which if set will raise LWTException indicating that the object already exists in the database and you cannot create it.

class User(Model):
    __table_name__ = 'user'
    _if_not_exists = True  

    user_id = UUID(primary_key=True)
    email = Text(max_length=120, primary_key=True)
    first_name = Text()
    last_name = Text()

as shown above setting _if_not_exists = True in the model solved my problem :)

Answered By - Crazyshezy