How to change type of field in model, when database is already populated ?

[mangu rajpurohit]

Hi,

I am new to Django. I am working on an application ,where the types of table fields in database are not known before hand. So, say for eg. In student table, I am assigning CharField to marks field, ie

class Student(models.Model):

     marks = model.CharField(max_length = 3)

and after Student table in database is populated, can I change the type of marks to IntegerField as shown below :-

class Student(models.Model):

     marks = model.IntegerField()

Is it possible ? If not feasible, then what are the alternatives ways/design strategies or what should be done in such cases ? If feasible, then what are its side-effects ?

Sorry for my poor english.

[Sergiy Khohlov]

Dump your data in the SQL file. Of course , separate structure and data. Update structure. Verify ability to switch into digit. If you have using Digit as string in dump you can update data manually or by see or ask. If previous data contains char then no chances.

16 трав. 2015 16:26 "mangu rajpurohit" <rajpuro...@gmail.com> пише:

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[donarb]

You can use the migration commands in Django to create new columns, then move and possibly convert the data to the new column.

https://docs.djangoproject.com/en/1.8/topics/migrations/#data-migrations

[Larry Martell]

Why can't you just alter the table:

alter table student modify marks int;

[Galia Ladiray]

From django 1.7 it is done by the migration

Change your Models class

run makemigrations, it will recognise the change and create a migration file

run migrate command, which will alter the database