You are trying to add a non-nullable field new field to userprofile without a default

Question

I know that from Django 1 7 I don t need to use South or any other migration system  so I am just using simple command python manage py makemigrations  However  all I get is this error    You are trying to add a non-nullable field  new field  to userprofile without a default  we can t do that  the database needs something to populate existing rows     Here is models py   class UserProfile models Model       user   models OneToOneField User      website   models URLField blank True      new field   models CharField max length 140    What are options

User · Answer

If you are in early development cycle and don t care about your current database data you can just remove it and then migrate  But first you need to clean migrations dir and remove its rows from table  django migrations   rm  your app migrations    rm db sqlite3 python manage py makemigrations python manage py migrate

User · Answer

I honestly fount the best way to get around this was to just create another model with all the fields that you require and named slightly different  Run migrations  Delete unused model and run migrations again  Voila

User · Answer

I was early in my development cycle  so this may not work for everyone  but I don t see why it wouldn t     I added blank True  null True to the columns where I was getting the error  Then I ran the python manage py makemigrations command    Immediately after running this command  and before running python manage py migrate   I removed the blank True  null True from all the columns  Then I ran python manage py makemigrations again  I was given an option to just change the columns myself  which I selected    Then I ran python manage py migrate and everything worked well

User · Answer

You can t add reference to table that have already data inside  Change   user   models OneToOneField User    to   user   models OneToOneField User  default         do   python manage py makemigrations python manage py migrate   change again   user   models OneToOneField User    do migration again   python manage py makemigrations python manage py migrate

User · Answer

In new file add the boolean property null   new field   models CharField max length 140  null True    after you run a   manage py syncdb for refresh the DB   and finally you run   manage py makemigrations  and   manage py migrate

User · Answer

In models py  class UserProfile models Model       user   models OneToOneField User      website   models URLField blank True      new field   models CharField max length 140  default  some value     You need to add some values as default

User · Answer

You need to provide a default value   new field   models CharField max length 140  default  SOME STRING

User · Answer

Do you already have database entries in the table UserProfile  If so  when you add new columns the DB doesn t know what to set it to because it can t be NULL  Therefore it asks you what you want to set those fields in the column new fields to  I had to delete all the rows from this table to solve the problem    I know this was answered some time ago  but I just ran into this problem and this was my solution  Hopefully it will help anyone new that sees this

User · Answer

In case anyone is setting a ForeignKey  you can just allow nullable fields without setting a default   new field   models ForeignKey model  null True    If you already have data stored within the database  you can also set a default value   new field   models ForeignKey model  default  lt existing model id here gt

User · Answer

What Django actually says is      Userprofile table has data in it and there might be new field values   which are null  but I do not know  so are you sure you want to mark   property as non nullable  because if you do you might get an error if   there are values with NULL   If you are sure that none of values in the userprofile table are NULL - fell free and ignore the warning    The best practice in such cases would be to create a RunPython migration to handle empty values as it states in option 2     2  Ignore for now  and let me handle existing rows with NULL myself  e g  because you added a RunPython or RunSQL operation to handle NULL values in a previous data migration    In RunPython migration you have to find all UserProfile instances with empty new field value and put a correct value there  or a default value as Django asks you to set in the model   You will get something like this     please keep in mind that new value can be an empty string  You decide whether it is a correct value  for profile in UserProfile objects filter new value  isnull True  iterator        profile new value   calculate value profile      profile save     better to use batch save   Have fun

User · Answer

You can use method from Django Doc from this page https   docs djangoproject com en 1 8 ref models fields  default  Create default and use it  def contact default       return   email    to1 example com    contact info   JSONField  ContactInfo   default contact default

User · Answer

If you are early into the development cycle you can try this -   Remove comment that model and all its usages  Apply migrations  That would delete that model and then add the model again  run migrations and you have a clean model with the new field added

User · Answer

One option is to declare a default value for  new field    new field   models CharField max length 140  default  DEFAULT VALUE     another option is to declare  new field  as a nullable field   new field   models CharField max length 140  null True    If you decide to accept  new field  as a nullable field you may want to accept  no input  as valid input for  new field   Then you have to add the blank True statement as well   new field   models CharField max length 140  blank True  null True    Even with null True and or blank True you can add a default value if necessary   new field   models CharField max length 140  default  DEFAULT VALUE   blank True  null True

User · Answer

If  website  can be empty than new field should also be set to be empty   Now if you want to add logic on save where if new field is empty to grab the value from  website  all you need to do is override the save function for your Model like this   class UserProfile models Model       user   models OneToOneField User      website   models URLField blank True  default  DEFAULT VALUE       new field   models CharField max length 140  blank True  default  DEFAULT VALUE        def save self   args    kwargs           if not self new field                Setting the value of new field with website s value             self new field   self website            Saving the object with the default save   function         super UserProfile  self  save  args    kwargs

User · Answer

If the SSH it gives you 2 options  choose number 1  and put  None   Just that   for the moment

User · Answer

If you are fine with truncating the table of the model in question  you can specify a one-off default value of None in the prompt  The migration will have superfluous default None while your code has no default  It can be applied just fine because there s no data in the table anymore which would require a default

[python] You are trying to add a non-nullable field 'new_field' to userprofile without a default

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