i'm a total noob in django and just wondering if it's possible for an admin doing a same thing at the same time ? the only thing i get after looking at the django documentation is that it is possible to have two admins, but is it possible for the admins to do a task in the same databases at the same time ?
thanks for any help
You didn't made it clear that what do you actually want but:
If by admin you mean a superuser then yes you can have as many admins as you want.
Admins can change anything in database at the same time, but if you mean changing a specific row of a specific table at the same time, its not possible because of these reasons:
Its kinda impossible to save something at the same time. when both admins tries to save anything, the last request will be saved (the first one will be saved too but it changes to the last request)
and if there is any important data in database, you should block any other accesses to that row till the first user has done his job and saved the changes. (imagine a ticket reservation website which has to block any other users to be allowed to order the same ticket number till user finishes the order or cancel it.)
Also if you mean 2 different django projects using a single database, then its another yes. Basically they are like 2 different admins and all above conditions works for them too.
Related
I will have a sidebar that appears on almost every page of my web app. The sidebar will have some drop-downs, which will consist of a total of say, 1000 different options, which are pulled from the db. Rather than doing the query to get these choices on every page load, I think it makes more sense to just do the query once, say in my config.py and store them in a variable that my views have access to. Is this OK? Is there a better way to accomplish this?
You could do that, but then you'd need to restart your Flask server every time you wanted to update the sidebar.
I'd use some other form of caching here. You could use Flask-Cache and memoize your query results. You can pick a nice long cache timeout, and then clear the cached result whenever you update the sidebar.
I have a multi-database Django Project (Python 2.7, Django 1.4 ) and I need that the database used in every single transaction triggered in a request be selected through the url from that request.
Ex:
url='db1.myproject.com'
Would trigger the use of 'db1' in every transaction, like this:
MyModel.objects.using('db1').all()
That is where my problem resides.
Its virtualy impossible include in every call of 'Model.objects' the '.using(dbname)' function (this project already have 2 dozen of models, and its build with scaling in mind, so it could have hundreds of models, and almost everymodel has (or might have) a implementation a of post_save/post_delete that acts as database triggers).
Is there a way of telling django that he should change the default database for this or that request ?
I already have a Custom QuerySet and a Custom Manager, so, if i could tell THEM the database should be this or that could do the trick to (i dont find anywhere how to get request data inside them).
Any help would be apreciated.
I think my answer to a similar question here will do what you need:
https://stackoverflow.com/a/21382032/202168
...although I'm a bit worried you may have chosen an unconventional or 'wrong' way of doing database load balancing, maybe this article can help with some better ideas:
http://engineering.hackerearth.com/2013/10/07/scaling-database-with-django-and-haproxy/
If you want user to submit say articles to your website but you want to approve these articles before they are added to a list of articles, how would you go about doing so?
The only method I can think of is to have 2 databases; one for 'awaiting approval' and another for 'approved and ready to be displayed'. However, my issue is whether there is a fast method to go about transferring the information between the two databases? I only know about doing this manually.
Or is there already a Django module that handles this?
Thank You for any help.
As jordi has said, add an extra field, but you might also want to write a custom manager for your table that selects posts according to status.
See the Django docs: https://docs.djangoproject.com/en/dev/topics/db/managers/ where they set up a manager that filters on sex="M" to only return Male people. This makes your code neater, and means as long as you go through the right manager you'll not have to keep remembering to test for state="Approved" all the time.
If you want to get more complex, the thing you are doing is called "Workflow" and there are django and python packages that implement this - but it gets very complex very quickly...
Just add a column to the database table called status
1 = waiting
2 = approved
3 = denied
I am trying to set up a system where every time something happens in the admin console (let's say, a user is saved), a certain set of people gets notified. I hooked up post_save and
it works fine. I can retrieve most of the data I need (which user and what fields were saved) from the instance passed into the callback function. However, there's one thing in the requirements, which I can't figure out how to do and that is to show, which particular admin made the change. Any ideas on how that can be done?
Thank you,
Luka
If you go through the database, you will discover that you have the table django_admin_log which lists what changes were made by what admin and even has a change_message . Maybe you can create a view for this table and play around with the queries.
I have an authentication backend based off a legacy database. When someone logs in using that database and there isn't a corresponding User record, I create one. What I'm wondering is if there is some way to alert the Django system to this fact, so that for example I can redirect the brand-new user to a different page.
The only thing I can think of is adding a flag to the users' profile record called something like is_new which is tested once and then set to False as soon as they're redirected.
Basically, I'm wondering if someone else has figured this out so I don't have to reinvent the wheel.
I found the easiest way to accomplish this is to do exactly as you've said. I had a similar requirement on one of my projects. We needed to show a "Don't forget to update your profile" message to any new member until they had visit their profile for the first time. The client wanted it quickly so we added a 'visited_profile' field to the User's profile and defaulted that to False.
We settled on this because it was super fast to implement, didn't require tinkering with the registration process, worked with existing users, and didn't require extra queries every page load (since the user and user profile is retrieved on every page already). Took us all of 10 minutes to add the field, run the South migration and put an if tag into the template.
There's two methods that I know of to determine if an object has been created:
1) When using get_or_create a tuple is returned of the form (obj, created) where created is a boolean indicating obviously enough whether the object was created or not
2) The post_save signal passes a created paramater, also a boolean, also indicating whether the object was created or not.
At the simplest level, you can use either of these two hooks to set a session var, that you can then check and redirect accordingly.
If you can get by with it, you could also directly redirect either after calling get_or_create or in the post_save signal.
You can use a file-based cache to store the users that aren't yet saved to the database. When the user logs in for the second time, you can look in the cache, find the user object, and save it to the database for good.
Here's some info on django caching: http://docs.djangoproject.com/en/dev/topics/cache/?from=olddocs
PS: don't use Memcached because it will delete all information in the situation of a computer crash or shut down.