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Create an estimator tool in Django Python

I am new to Django. I have read the official documentations and managed to create models in Django. I have a task to create an estimator tool that could provide the estimate(cost) to the user when he selects the hardware/softwares etc. This could be something similar to this http://calculator.s3.amazonaws.com/index.html. This is only for reference but I want to add details dynamically.
Basically I am curious to know about:
How to add rows in Django?
How is the 'Monthly cost' working in amazon calculator?
I want to achieve something similar to this dynamic estimations.
Any pointers/articles/suggestions will be helpful in my learning and analysis.

You have to override the Django admin template for that.
How to add button next to Add User button in Django Admin Site
for auto-selecting the group value you can use
https://github.com/crucialfelix/django-ajax-selects

Django Forum App Project Structure

EDIT: I'm new to this site but if you are going to down vote me, could you perhaps explain why? I've searched Google, this site and others but have not found anything that makes any sense and I thought this was a site to ask questions and get some help.
I've got a Custom PHP Forum that I am trying to convert to Python/Django as a learning experience and I'm having some problems. I've been reading up on Django and it is encouraged that our application is split into multiple apps. I went through the 6 part tutorial and many other parts of the documentation but I'm left with some questions.
Let's assume that I have about 30 tables.
Tables such as:
posts_index, posts, users, user_groups, user_activity, user_sessions, forums, payment_gateways, payment_logs, etc for a basic forum
I'm having issues structuring my models. With PHP all I needed was index.php, /admin/index.php, view_forum.php, view_thread.php and a few others, everything could pull directly from the database and I had no issues but now I have to deal with apps/modules.
I'm thinking I'd need to structure my apps in a manner similar to this:
/admin/ app
/forums/ app
/view_forum/ app
/view_thread/ app
/forums/view_forum/ app (instead of just /view_forum/, could be a sub app)
/forums/view_thread/ app (instead of /view_thread/, could be a sub app)
My problem and only question here is dealing with global state. For example Users/Group/Session/Logging/Permission information is going to need to be shared across multiple apps through importing in the other apps models file. To do this I need to reference their model information, what is the correct way to handle this?
Would either of these be acceptable?
Create a ton of different apps such as /users/ which would model my users_groups, users, user_sessions, another app for /posts/ that would include models for posts_index, forums, and so forth with these models existing but not actually being used publicly, they would be used in other apps only. They would be imported in areas such as the /view_forum/ app since when viewing a forum I might need to determine if the user is logged in, is a member of a particular group, etc and because of that would need access to a number of the hidden apps and hence would be imported from the hidden app.
What if I just had one single app, instead of it being an app it would just be my entire project. This sounds like the best solution to me but it seems to be suggested if we cannot summarize the entire application into a sentence it needs to be broken up. If I went with one single app being used as my entire project, my models file will have 30+ different models, is this acceptable? I assume not but figured I'd ask.
Do either of the above make any sense? If not what would you do fix it? I'll admit I'm lost so any feedback would mean a lot.
I'm new to Python/Django and am trying to figure things out. I hope I am clear on what I am trying to do. I'm more than welcome to any advice. I've been trying to play around with things but I figure it would be better to ask for advice from more experienced developers. I'm not a professional programmer and am still learning so please be nice :).

I have voted this up... I had similar questions when I first moved to Django (also coming from PHP)
Try not to think of apps in terms of db tables (or url paths), you want to create apps for independent pieces of functionality.
I would say most of your code will be in a single forum app with Forum and Post models in it and all your forum-related urls like /view_forum/ and /view_thread/. Note there's not really such thing as a sub-app in Django... these are different views which all belong to one related set of functionality in a single app.
The 'users' stuff... you normally want to hook in to the Django auth system (https://docs.djangoproject.com/en/dev/topics/auth/default/#user-objects) though if you are trying to keep the legacy database structure this may be harder... you may end up needing your own users app.
The payment gateways stuff sounds like another app again.
For the admin, you get this (almost) for free with Django:
https://docs.djangoproject.com/en/1.5/ref/contrib/admin/
You need an admin.py inside each app, where you register the models that you want to expose to the admin site.
You might find it's best to follow a tutorial and build a simple blog (or try and build a very simple minimal forum from scratch) to get a feel for Django before tackling your re-write. Because trying to exactly recreate the old functionality with legacy db tables will be a bit harder and may lead you into patterns which are not 'good Django'.
You might also find it useful to look at the source code of an existing Django forum app, such as this one:
https://bitbucket.org/slav0nic/djangobb/src/
They have just a single djangobb_forum app that does everything. I think this is entirely justified as a forum is a single complicated piece of functionality.
Note how their Profile model effectively extends the built-in Django auth.User model via a OneToOneField. It makes it easier to integrate with the built-in login and authentication system that way.

Start by integrating your legacy database and then build the Admin site. You'll see how the model information is available to the Admin app and every other app you write. The key is to import models in your apps.

Django AdminSite - Difficult or Easy Implementation?

Has anyone implemented their own AdminSite? How easy/hard was the basic implementation?
I'm in the midst of building a "cms" that's going to be quite large and decently complex in some areas and I'm wondering if using something like AdminSite would save some time. I'd rather not have to make my own implementation for admin actions and inlines and the like (I know I can just use inline forms but that's not as simple as inlines = [Foo]).
When using a custom AdminSite, is further customization equivalent to customizing the standard Django admin?

You've read the admin site docs. It's a lengthy document, but two main hooks for adding custom functionality is through custom urls and modified standard views in your own AdminSite and ModelAdmin objects. Once you hook those in and the urls get mapped, it's just like building any other Django application, only that the templates aren't yours, so they're are a bit hard to manage and take getting used to. But it allows you to do additional gymnastics, like adding a form wizard to the admin site or splitting everything into multiple forms and rendering them in a single HTML form element in the templates, doing custom handling of GET/POST requests, etc.
I've used it in the past to create views for displaying custom reports and to create custom editing scenarios for the staff. My opinion is that you should KISS as much as possible. The admin site is all about generic views and generic presentation. Do expand, but be cautious if you override template blocks and think twice before you override something that's not wrapped in a block. Certain admin site features have certain presentation assumptions and the JS client app that's shipped with Django makes some too (that's what I've figured when working with adding dynamic inline models way back), so it'd be quite an undertaking if you'd like to roll a completely different presentation.
The answer in any case is YES! The admin site will provide you with more features for managing your model data interactively. I don't know how extensively you'd need to customize the admin, but there are CMSs, dedicated admin apps and admin integrated apps that are a real eye-opener. Django CMS, as I recalled, has been praised as the best open-source Django CMS out there and from what I can see it rolls it's own cust change/list views. Rosetta is an admin site only app that allows you to edit your translation files interactively and has an exhaustive admin interface! If you shop around on bitbucket and github you'll find many more examples, it should help you figure out best how much effort you'd need to put into it.

Both
If you are OK with it not doing exactly what you want its pretty much done for you automatically. If you need fine grain control over certain things it can be hard to customize without knowing the internals of the admin code.

the django admin is more of a one size fits all kind of ui which may not be intuitive for use in some cases ..
customizing its look is easy but extending it is some how hard. you are better off designing your own views in that case.

Is Django admin difficult to customize?

I have been playing for a couple of days with Django Admin to explore it, but I am still clueless of how it can be customized in the way we need.
Every time I look for any help for the customization in the admin panel, what I find is, a bunch of articles on various communities and forums, explaining how to customize the template, the lists items, the the column views etc. But that should not be called Django Customization.
If I need to make even a small change in the User functionality or any modification to the auth module. It takes a lots of efforts even in figuring out how that can be done.
Is Django that difficult to customize or its just lack of the help available over internet for this or its me who is moving in the wrong direction ?

You are not providing enough details on what you want to achieve, so it's difficult to say how complex the task is. You might also want to consider not modifying the admin site at all and building your own views where appropriate.
However, here are some good links to get you started:
Customizing the Django Admin
Doing more with the Django admin
Extending Django's User Admin

Personally, if you want a site to look like the admin, why not pull the templates and styles and use them, build your own views for what you need. Gobs of documentation and forum help is there for that. I like the idea of customizing the admin, but honestly, I have been doing it for awhile on a project and time and time again I think to myself, if this was built in the standard MVC (or MTV) manner with free templates online, copied admin ones, or some professionally made ones, and built with the plethora of addons and my code, it would be much easier!!! And, when you decide that request/response isn't cutting it, and you want to add lots of JavaScript, you'll be glad. I know. I have had to put all sorts of JavaScript on our Admin project. Mostly because it's impossible to make the admin do what we want, so we fix it with JavaScript once it is on screen. When you find yourself writing an Ajax based system, you'll wonder why you have the admin at all.
If I could start this project over, I might not even use Django, but I probably would. I most certainly won't used the Admin.
Now, if you are building an basic CRUD type site that doesn't have style-eyed users, then Django with grappelli, and some elbow grease will get the job done. Remember, Django is a collection of Python scripts. Just override everything you can, and you'll get there, if you aren't too ambitious.

Django Admin is easy to customize if your requirements match what is customizable in Django. If you need fancy features that are not out-of-the-box functionality you either need to find a plugin that does it, or implement it yourself by subclassing the appropriate classes. Which can be difficult, and requires good understanding of the internals of Django.
So in summary: it makes it easier to setup an admin, but if you need anything special that's not out of the box: you got a steep learning curve.
Depending on your requirements you can choose to use django or not. Anything that requires a lot of functional speccing is better of implemented manually.

It's very easy . Just copy default template to project and change HTML and some variable location
Just see in this vedio
https://youtu.be/NTZfjwf4F8A

MVC and django fundamentals

Pretty new to this scene and trying to find some documentation to adopt best practices. We're building a fairly large content site which will consist of various media catalogs and I'm trying to find some comparable data / architectural models so that we can get a better idea of the approach we should use using a framework we've never made use of before. Any insight / help would be greatly appreciated!

"data / architectural models so that we can get a better idea of the approach we should use using a framework we've never made use of before"
Django imposes best practices on you. You don't have a lot of choices and can't make a lot of mistakes.
MVC (while a noble aspiration) is implemented as follows:
Data is defined in "models.py" files using the Django ORM models.
urls.py file maps URL to view function. Pick your URL's wisely.
View function does all processing, making use of models and methods in models
Presentation (via HTML templates) invoked by View function. Essentially no processing can be done in presentation, just lightweight iteration and decision-making
The model is defined for you. Just stick to what Django does naturally and you'll be happy.
Architecturally, you usually have a stack like this.
Apache does two things.
serves static content directly and immediately
hands dynamic URL to Django (via mod_python, mod_wsgi or mod_fastcgi). Django apps map URL to view functions (which access to database (via ORM/model) and display via templates.
Database used by Django view functions.
The architecture is well-defined for you. Just stick to what Django does naturally and you'll be happy.
Feel free to read the Django documentation. It's excellent; perhaps the best there is.

first, forget all MVC mantra. it's important to have a good layered structure, but MVC (as defined originally) isn't one, it was a modular structure, where each GUI module is split in these tree submodules. nothing to use on the web here.
in web development, it really pays to have a layered structure, where the most important layer is the storage/modelling one, which came to be called model layer. on top of that, you need a few other layers but they're really not anything like views and controllers in the GUI world.
the Django layers are roughly:
storage/modelling: models.py, obviously. try to put most of the 'working' concepts there. all the relationships, all the operations should be implemented here.
dispatching: mostly in urls.py. here you turn your URL scheme into code paths. think of it like a big switch() statement. try hard to have readable URLs, which map into user intentions. it will help a lot to add new functionality, or new ways to do the same things (like an AJAX UI later).
gathering: mostly the view functions, both yours and the prebuilt generic views. here you simply gather all the from the models to satisfy a user request. in surprisingly many cases, it just have to pick a single model instance, and everything else can be retrieved from relationships. for these URLs, a generic view is enough.
presentation: the templates. if the view gives you the data you need, it's simple enough to turn it into a webpage. it's here where you'll thank that the model classes have good accessors to get any kind of relevant data from any given instance.

To understand django fundementals and the django take on MVC, consult the following:
http://www.djangobook.com/
As a starting point to getting your hands dirty with ...
"...trying to find some comparable data / architectural models"
Here is a quick and dirty way to reverse engineer a database to get a models.py file,
which you can then inspect to see how django would handle it.
1.) get an er diagram that closely matches your target. For example something like this
http://www.databaseanswers.org/data_models/product_catalogs/index.htm
2.) create an sql script from the er diagram and create the database,
I suggest Postgre, as some MySQL
table type will not have forgien key constraints, but in a pinch MySQL or SQLITE
will do
3.) create and configure a django app to use that database. Then run:
python manage.py inspectdb
This will at least give you a models.py file which you can read to see how django attempts
to model it.
Note that the inspect command is intended to be a shortcut for dealing with legacy
database when developing in django, and as such is not perfect. Be sure to read the
following before attempting this:
http://docs.djangoproject.com/en/dev/ref/django-admin/#ref-django-admin