CODEWITHSUNDEEP
pythondjangopython-2.7django-models
CDoc
CDoc

Reputation: 397

Django get last record -1 from database

I am doing a Save in every move of my django project (a game actually), and all I am trying to do is to get the LAST data I saved in the database in every new "click".

newsave = Save()
newsave.user = save.user
myList = json.loads(newsave.myField) # Read previous here, here is the problem
... (do some changes on myList) ...
newsave.myField = json.dumps(myList) # Save the new move, UPDATED

The problem is that I don't know how to read the previous move correctly.

Upvotes: 0

Views: 763

Answers (2)

pkisztelinski
pkisztelinski

Reputation: 542

Maybe django signals would help? https://docs.djangoproject.com/en/1.11/ref/signals/#pre-save or https://docs.djangoproject.com/en/1.11/ref/signals/#post-save?

Upvotes: 0

Jose Cherian
Jose Cherian

Reputation: 7707

First of all, you might want to rename your model from Save to something else as it will make your code much more easier to understand.(Django models already have a built in save() method)

One technique to handle this is by overriding the save() method of your model.In this case, you need the last record and not last-1 as the current record is not yet in the db.

Make sure that your model is storing the date&time of the last move so that you can accurately track the moves. 

from datetime import datetime
class Yourmodel(models.Model):
    modified = models.DateTimeField()

    def save(self, *args, **kwargs):
        ''' On save, update timestamps '''
        self.modified = datetime.now()
        #Get the last object, current object havent inserted to db yet.
        lastmove = Yourmodel.objects.latest('modified') 
         #do something to your lastmove.myfield here
         #you can access the current myfield using self.myfield 
        return super(Yourmodel, self).save(*args, **kwargs)

Upvotes: 1

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