In my web django, I do a query of Models.objects.all() or actually any other models in the views.py. It returns me a [,] value (empty array) - view from logs. However back in the manage.py shell, it is able to retrieve the objects. In mysql database, the data entries are there!
I have no idea how to debug from here, is there a way to resolve this error? This is not my first time. I have been doing django project for several months already. Only today, it is giving me this problem.
EDIT : This problem is very weird, I'm just curious whether anybody has encountered this problem before, I'm using Eclipse to edit the scripts(views.py, models.py etc).
Do you have __repr__ defined for your objects? Take a look at the HTML source generated by Django -- there's a good chance it looks like:
[<Model: model object>, <Model: model object>, ...]
Your web browser then interprets the <...> as an HTML tag that it doesn't understand, and thus can't render, and displays only the content outside the tags (the "[", ",", and "]" characters).
Related
I have written a small django app and in it I can upload some documents and at another point I can make a reference from a payment to the corresponding document. But my problem is that the list of documents is always outdated. But when I kill my gunicorn and start the webserver again, then the dropdown list with documents loads correctly and also shows the newest file uploads.
Do you have an idea why Django behaves like that?
Best regards
Edit: I just saw that I have to edit this question.
So I have this in my forms.py:
dms_objects = dmsdok.objects.all().order_by('-id')
choices_dms = []
for dms_obj in dms_objects:
choices_dms.append((dms_obj.id, dms_obj.dms_dok_titel))
And also I have this in the form:
zahlung_dok_pseudo_fk = forms.IntegerField(required=False, widget=forms.Select(attrs={'class':'form-control',}, choices= choices_dms), label='Zugehörigkeit Dokument')
I guess that this is what Willem means, but I do not know how I must change that.
I am trying to save an array of text containing category types for a hotel system which looks something like this ['category-1', category-2', category-3, category-4] . I am using category_type = ArrayField(models.CharField(max_length=200),null=True) in my models.py
The error i get is
malformed array literal: "" LINE 1: ..., '{category-1,
category-2}'::varchar(200)[], ''::varcha...
^ DETAIL: Array value must start with "{" or dimension information.
The error persist even after processing python list from ['category-1', category-2', category-3, category-4] to {category-1, category-2, category-3, category-4}.
I have gone through postgresql documentation and have found very limited help,
https://pganalyze.com/docs/log-insights/app-errors/U114 this is something similar posted to what i am facing problem with.
Could someone please tell me what am i doing wrong? Any help would be appreciated.
EDIT:
Following is in my View.py
hotel_category=categoryTable(category_type=categorytype)
hotel_category.save()
and i am using categorytype=request.POST.getlist('category-type') in my Views.py to get it from the POST request after user submits the form. This returns a Python list that i have mentioned above, i have manipulated this list to match PostgreSQL ArrayField with '{','}' but i still have this error. If there is anything else you would like me to add, please let me know. :)
This is an update/answer to my question for anyone who faces this issue in the future. After struggling to find help from different resources, i decided to use JSON string to store my python list.
I am using :
categorytype = json.dumps(request.POST.getlist('category-type'))
to encode and using JSONDecoder() to fetch from database and decode. I have no idea how would this impact my further development but for now it seems a decent approach since personally i think ArrayFields are not well supported and documented in Django.
I will keep this post updated as i progress further on how this approach has impacted my development.
Have a nice day.
My django app uses update_or_create() to update a bunch of records. In some cases, updates are really few within a ton of records, and it would be nice to know what got updated within those records. Is it possible to know what got updated (i.e fields whose values got changed)? If not, does any one has ideas of workarounds to achieve that?
This will be invoked from the shell, so ideally it would be nice to be prompted for confirmation just before a value is being changed within update_or_create(), but if not that, knowing what got changed will also help.
Update (more context): Thought I'd give more context here. The data in this Django app gets updated through various means (through users coming on the web site, through the admin page, through scripts (run from the shell) that populate data from a csv etc.). The above question is important mostly for the shell scripts that update data from csvs, hence a solution at the database/trigger/signal level may not be helpful here (I guess).
This is what I ended up doing:
for row in reader:
school_obj0, created = Org.objects.get_or_create(school_id = row[0])
if (school_obj0.name != row[1]):
print (school_obj0.name, '==>', row[1])
confirmation = input('proceed? [y/n]: ')
if (confirmation == 'y'):
school_obj1, created = Org.objects.update_or_create(
school_id = row[0], defaults={"name": row[1],})
Happy to know about improvements to this approach (please see the update in the question with more context)
This will be invoked from the shell, so ideally it would be nice to be
prompted for confirmation just before a value is being changed
Unfortunately, databases don't work like that. It's the responsibility of applications to provide this functionality. And django isn't an application. You can however use django to write an application that provides this functionality.
As for finding out whether an object was updated or created, that's what the return value gives you. A tuple where the second value is a flag for update or create
I'm trying to learn how to use the ContentTypes framework, I can't seem to get it to find my own apps.
The docs have clear instructions for importing a model from django.contrib.sites, which works for me. However, when I try to substitute my own app and model, I am unsuccessful.
I have a model at MyApp.Events.models.Event. I try to call:
i = ContentType.objects.get(app_label="Events", model="Event")
in response, console prints:
django.contrib.contenttypes.models.DoesNotExist: ContentType matching
query does not exist.
I tried this as well which also failed:
i = ContentType.objects.get(app_label="events", model="event")
I have 'django.contrib.contenttypes' as well as this app listed under installed apps. Is there another setting I am missing to enable this functionality?
Since no one else posted it, here is the solution.
i = ContentType.objects.get(app_label="Events", model="event")
Even if your model is capitalized in your models.py, it gets saved in all lowercase. I don't know if this is Django's idea of funny or PostgreSQL's, so your mileage may vary.
I just set up the environment for an existing Django project, on a new Mac. I know for certain there is nothing wrong with the code itself (just cloned the repo), but for some reason, Django can't seem to retrieve data from the database.
I know the correct tables and data is in the db.
I know the codebase is as it should be.
I can make queries using the Django shell.
Django doesn't throw any errors despite the data missing on the web page.
I realize that it's hard to debug this without further information, but I would really appreciate a finger pointing me to the right direction. I can't seem to find any useful logs.
EDIT:
I just realized the problem lies elsewhere. Unfortunately I can't delete this post with the bounty still open.
Without seeing any code, I can only suggest some general advice that might help you debug your problem. Please add a link to your repository if you can or some snippets of your database settings, the view which includes the database queries etc...
Debugging the view
The first thing I would recommend is using the python debugger inside the view which queries the database. If you've not used pdb before, it's a life saver which allows you to set breakpoints in your Python script and then interactively execute code inside the interpreter
>>> import pdb
>>> pdb.set_trace()
>>> # look at the results of your queries
If you are using the Django ORM, the QuerySet returned from the query should have all the data you expect.
If it doesn't then you need to look into your database configuration in settings.py.
If it does, then you must might not be returning that object to the template? Unlikely as you said the code was the same, but double check the objects you pass with your HttpResponse object.
Debugging the database settings
If you can query the database using the project settings inside settings.py from the django shell it sounds unlikley that there is a problem with this - but like everything double check.
You said that you've set up a new project on a mac. What is on a different operating system before? Maybe there is a problem with the paths now - to make your project platform independent remember to use the os.path.join() method when working with file paths.
And what about the username and password details....
Debugging the template
Maybe your template is referencing the wrong object variable name or object attribute.You mentioned that
Django doesn't throw any errors despite the data missing on the web
page.
This doesn't really tell us much - to quote the Django docs -
If you use a variable that doesn’t exist, the template system will
insert the value of the TEMPLATE_STRING_IF_INVALID setting, which is
set to '' (the empty string) by default.
So to check all the variables available to your template, you could use the debug template tag
{{ debug }}
Probably even better though is to use the django-debugging-toolbar - this will also let you examine the SQL queries your view is making.
Missing Modules
I would expect this to raise an exception if this were the problem, but have you checked that you have the psycopg module on your new machine?