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Is there a way to automatically generate a whole system for different users [duplicate]

I have developed Multi-tenant SAAS apps in PHP/Laravel but recently I had a challenge to develop one in Django/Python. I am still learning Django though and I really like Django rest framework (DRF). But I have difficulties to figure out the highlighted areas below, If someone shows some light, I will be good to go:
How to handle subdomains/domains and selecting the right tenant db
How to manage and dynamically handle different database in django
Can multi-tenant apps backend still be managed from Django admin interface
I will be using queues and other apps scalling techniques, need tips and tricks if any
Any example out there
Any challenge experience when developing SAAS through Django

Well...
django-subdomains
There are people who asked in SO questions about dynamic databases in django (including, ahem... me). I'm not entirely sure I understood what you mean by "dynamically handle different database" so I guess just go to the links I just mentioned and pick out the best one for your project. (also - perhaps this is more relevant?)
Check out django-multitenant-schemas and this answer too.
There was a video of the guys behind Disqus (one of the largest django app in the world) explaining how they handle scaling. Here another interesting article on the subject. Also, the legendary SO question Does Django Scale.
(and 6.) Check out this answer
I hope that's detailed enough. I know this might be a disappointing only-links answer, but this is the reality of it - Django is a newer framework, and web development with python is still less common than php. With that in mind, understand that for all the awesomness of django (and it is awesome), with more complex needs there's more you'll have to do yourself.
In this case, you'll have to figure out how to do each part of the way seperatly and then combine it all. You can easily find a way to create a REST django app for example, but then you'll need to figure out how to combine it with another package (such as the above subdomains).
You can find a million examples out there of people doing freaky things with django. It's really powerful (when I learned about dynamic models I was blown away). But the more complex your app, the more you'll need to do yourself.
Pick it up, one step at a time, and come back to SO with specific issues you're having (or the django users google group). Good luck!

Neo4j and django models

So, I'm looking into the Django and Neo4j integration, but there's not much about it out there ... What I want to know is if I have a model like the one here:
If I want to add a new property to a model, it would be as simple as doing:
node.setProperty( "newProperty", "something" );
??
Moreover, all the queries in django would work ? How is the traversing made ?
I would appreciate any response
:D
Thanks.

We've been working on updating the Neo4j/Django integration to work with neo4j-rest-client - the fruits of our labor are on GitHub, with some quick comments on my blog.
There are some pros and cons to our integration. The most obviously impacting is our use of a REST client- you get to use a remote database, while losing quite a bit, performance-wise. OTOH, the integration works alongside a relational database, so you can still use django.contrib stuff that relies on the original ORM, and it handles indexing and query sets pretty nicely.
To do what you want above using neo4django, you'd simply get the neo4j-rest-client based node from the model instance, and have at it.
model_instance.node['newProperty'] = 'something'
We're still cranking on making the integration more dynamic, supporting traversals/etc in a Pythonic way, and (currently most important) improving the performance. If you're interested, I'd love feedback.

Have you seen Tobias's blog post about Django integration? It's kinda old now, but still relevant. Plus there are examples you can check out too.

Django, Turbo Gears, Web2Py, which is better for what?

I got a project in mind that makes it worth to finally take the plunge into programming.
After reading a lot of stuff, here and elsewhere, I'm set on making Python the one I learn for now, over C# or java. What convinced me the most was actually Paul Graham's excursions on programming languages and Lisp, though Arc is in the experimental stage, which wouldn't help me do this web app right now.
As for web app fast, I've checked out Django, Turbo Gears and Py2Web. In spite of spending a lot of time reading, I still have no clue which one I should use.
1) Django certainly has the nicest online presence, and a nicely done onsite tutorial, they sure know how to show off their thing.
2) Web2Py attracted me with its no-install-needed and the claim of making Django look complicated. But when you dig around on their website, you quickly find content that hasn't been updated in years with broken external links... There's ghosts on that website that make someone not intimately familiar with the project worry if it might be flatlining.
3) Turbo Gears ...I guess its modular too. People who wrote about it loved it... I couldn't find anything specific that might make it special over Django.
I haven't decided on an IDE yet, though I read all the answers to the Intellisense code completion post here. Showing extra code snippets would be cool too for noobs like me, but I suppose I should choose my web frame work first and then pick an editor that will work well with it.
Since probably no framework is hands down the best at everything, I will give some specifics on the app I want to build:
It will use MySQL, it needs register/sign-in, and there will be a load of simple math operations on data from input and SQL queries. I've completed a functional prototype in Excel, so I know exactly what I want to build, which I hope will help me overcome my noobness. I'll be a small app, nothing big.
And I don't want to see any HTML while building it ;-)
PS: thanks to the people running Stackoverflow, found this place just at the right moment too!

You should look at the web2py online documentation (http://web2py.com/book). It comes with a Role Based Access Control (the most general access control mechanism) and it is very granular, you can grant access for specific operation on specific records. It comes with a web based IDE but you can use WingIDE, Eclipse and PyCharm too. It comes with helper system that allows you to generate HTML without using HTML. Here is an example of a complete app that requires users to register/login/post messages:
db.define_table('message',Field('body'),Field('author',db.auth_user))
#auth.requires_login()
def index():
db.message.author.default=auth.user.id
db.message.author.writable=False
return dict(form=crud.create(db.message),
messages=db(db.message.id>0).select())
The web2py project is very active as you can see from the list of changes http://code.google.com/p/web2py/source/list
If you have web2py related questions I strongly suggest you join the web2py mailing list:
http://groups.google.com/group/web2py/topics
We are very active and your questions will be answered very quickly.

I have to say as not particularly skilled developer, the speed at which I have been able to create using web2py has blown my mind. In large part due to the amazing community and the core value Massimo has of making the framework accessible.
When I started I had written 0 lines of code in Python
Never heard of web2py
I've been at it seriously for about a month and have progressed (in my usual fashion) from asking questions that no one could answer (because they didn't make any sense) to coding for hours at a time without picking up a book or asking a question.
I'm really impressed.

I've had positive experiences with Django.
Built-In Authentication and easy to use extensions for registration
Very good documentation
You probable write your HTML templates mostly in base.html, then just use template inheritance (Note: You'll need to write at least a little bit of HTML)
In contrast to Turbogears, Django is more 'out-of-the-box'
I don't have any experience with web2py, but from my impression, it tries to do a little to much 'out-of-the-box'

If you decide to go with Django, make sure that you use its Generic Views. They will save you from writing lots of code, both Python and HTML.
Also, unless there is a very specific reason for you to use MySQL, I advise you to switch to PostgreSQL. Django is much more oriented towards PostgreSQL and it's a much better database anyway.
The online Django documentation is great, this is what put it apart from all the other frameworks. I also recommend the book Practical Django Projects by James Bennett

Django: Heard it has the best administrative
interface. But uses it's own ORM, i.e. doesn't use SQL-Alchemy.
Web2py: Didn't research this.
Turbogears2:
Uses SQL-Alchemy by default, uses Catwalk for admin
interface, but documentation isn't as
great.
I chose Turbogears2 because it uses popular components, so I didn't have to learn anything new...

I've used both web2py and RoR extensively, and while RoR has gotten a lot of popularity and support in the past few years, web2py is simpler, cleaner, less "magical", and yet also offers more (useful) out-of-the-box functionality. I'd say that web2py has more potential than RoR, but it is a relatively new framework and does yet not have the maturity of RoR. (Despite that, though, I'd choose web2py over RoR any day...)

If you "don't want to see any HTML while building it" then you can forget Django. It is not focused on "point-click-done," it is focused on pros going from concept to production in the shortest time possible. The hierarchical nature of the templating language can lead to some very clean overall site layouts. I use Django for all of my larger sites and I love it.
Although it's written in PHP, not Python, you might take a look at the major new version of WordPress that came out about 2 or 3 months ago. In 3.0 they have come a long way from being a "blogs only" environment and there are tons of ready-made templates for it. Of course if you want to tweak a template, well, there's that nasty old HTML again. I am considering using it for my smaller clients that can't deal with the admin of a dedicated server, etc., that tends to come with a Django site.
Update:
Ah, I missed the semi-joke -- I was up too early and that tends to make me tone deaf to humor. As far as using templates from existing sites, I have done this quite successfully with a couple of sites, both those that were static and those originally driven by well-written PHP scripts. I recommend a careful reading of the {% extends %} and {% include %} docs. Both take either a string literal or a variable. I have used the later method and it can be quite useful for a site that has strong hierarchy distinguished by style changes across branches.
It is also worth the time to understand the search order for templates -- it can be used to good effect, but it can be puzzling if you don't grok it. See the template-related items in the settings.py file for this and other useful goodies.

How to generate basic CRUD functionality in python given a database tables

I want to develop a desktop application using python with basic crud operation. Is there any library in python that can generate a code for CRUD functionality and user interface given a database table.

Hopefully, this won't be the best option you end up with, but, in the tradition of using web-interfaces for desktop applications, you could always try django. I would particularLY take a look at the inspectdb command, which will generate the ORM code for you.
The advantage is that it won't require that much code to get off the ground, and if you just want to use it from the desktop, you don't need a webserver; you can use the provided test server. The bundled admin site is easy to get off the ground, and flexible up to a point; past which people seem to invest a lot of time battling it (probably a testimony to how helpful it is at first).
There are many disadvantages, not the least of which is the possibility of having to use html/javascript/css when you want to start customizing a lot.

If it were me, I would consider borrowing django's ORM, but then again, I'm already familiar with it.
Having said that, I like working with it, it's usable outside the framework, and it will give you mysql, postgres, or sqlite support. You could also hook up the django admin site to your models and have a web-based editor.
There are surely other ORMs and code generators out there too (I hope some python gurus will point some out, I'm kind of curious).

If you want something really small and simple, I like the Autumn ORM.
If you use the Django ORM, you can use the automatically-generated Django admin interface, which is really nice. It's basically a web-based GUI for browsing and editing records in your database.
If you think you will need advanced SQL features, SQLAlchemy is a good way to go. I suspect for a desktop application, Django or Autumn would be better.
There are other Python ORMs, such as Storm. Do a Google search on "python ORM". See also the discussion on this web site: What are some good Python ORM solutions?

Does anyone know about workflow frameworks/libraries in Python?

I'm searching for a workflow library/framework for Python. I'm astonished that there I cannot find anything which is simple and not attached to Zope/Plone.
Does anyone know of an open-source, simple workflow library/framework. It's preferred to support Django, but not required.

Try GoFlow, a workflow engine for Django.

Unfortunately it seems like most/all of the projects listed here are no longer active. Here's a new project which is currently ongoing:
http://packages.python.org/django-workflows/overview.html

Another workflow project that I saw recently was repoze.workflow, which is a state-machine based workflow engine which was inspired by plone, but is a clean re-implementation.
http://svn.repoze.org/repoze.workflow/trunk/docs/index.rst
Not exactly sure how production ready it really is, but I do know some people that are using it.

I used hurry.workflow: http://pypi.python.org/pypi/hurry.workflow
It has plenty of features but unfortunately has some zope dependecies so it may be not applicable for other frameworks.

We are actively working on Zops Workflow Engine based on Spiff. You can check if it suits your needs.
https://github.com/zetaops/zengine

I know there is an openerp, but it's not workflow.....

Besides GoFlow (linked in Oli's answer) the only other Django workflow I know of is part of the Pinax project.
More generally for Python based workflows there is spiff workflow and Dave Kuhlman's Workflow and REST How-to that could probably be converted from Quixote to Django.

ntoll's workflow for django is alpha, but is actively developed

There is also Xworkflows ( https://github.com/rbarrois/xworkflows/ ) and it's pluggable to django with django-xworkflofws ( https://github.com/rbarrois/django_xworkflows )

Have you thought about building workflows with rules? You might checkout http://nebrios.com, a rules based workflow tool. It's built in Python/Django and executes full Python and Django. It's not FOSS though, and doesn't integrate as a library since it's Platform.
Full Disclosure: We built this over the last year since we couldn't find any workflow/process tools that met our needs.