If you want to extract UML diagram from your Django models you can use the [Graph models][1] command of [django-extensions][2]. Another one that do mostly the same thing: [django-graphviz][3].

If you want to create your Django models from UML: [uml-to-django][4].

And to create UML diagrams, there&#39;s [Dia][5], [yED][6] and [ArgoUML][7]

You can check also this [list of tools.][8]


  [1]: http://django-extensions.readthedocs.org/en/latest/graph_models.html
  [2]: https://github.com/django-extensions/django-extensions
  [3]: http://code.google.com/p/django-graphviz/
  [4]: http://code.google.com/p/uml-to-django/
  [5]: http://projects.gnome.org/dia/
  [6]: http://www.yworks.com/en/products_yed_about.html
  [7]: http://argouml.tigris.org/
  [8]: http://modeling-languages.com/uml-tools/#python

Best I can think of is [Argo UML][3] which requires you to design by hand (and then you can convert the UML into Django with [this tool][1])

If you want to do django - uml conversion (the other way) try looking at [Django To UML][2]


  [1]: http://code.google.com/p/uml-to-django/
  [2]: http://jaredforsyth.com/blog/2010/apr/29/django-uml/
  [3]: http://argouml.tigris.org/

I am writing a glossary page. I have the alphabet links on the top of the page. I want to keep the top of the page (including the alphabet links) fixed, whilst the section of the page with the definitions, scrolls up/down as an alphabet is clicked.

My HTML looks a bit like this:

    &lt;html&gt;
    &lt;head&gt;&lt;title&gt;My Glossary&lt;/title&gt;&lt;/head&gt;
    &lt;body&gt;
            &lt;div id=&quot;top&quot;&gt;
                &lt;a href=&quot;#A&quot;&gt;A&lt;/a&gt; |
                 &lt;a href=&quot;#B&quot;&gt;B&lt;/a&gt; |
                &lt;a href=&quot;#Z&quot;&gt;Z&lt;/a&gt;
            &lt;/div&gt;
    
            &lt;div id=&quot;term-defs&quot;&gt;
               &lt;dl&gt;
                   &lt;span id=&quot;A&quot;&gt;&lt;/span&gt;
                   &lt;dt&gt;foo&lt;/dt&gt;
                   &lt;dd&gt;This is the sound made by a fool&lt;/dd&gt;
                   &lt;!-- and so on ... --&gt;
               &lt;/dl&gt;
            &lt;/div&gt;
    &lt;/body&gt;
    &lt;/html&gt;

**[Edit]**

The kind of effect I am trying to create is similar to the one [here][1]. The difference being that in the example in the link, the page scrolling is done when a user clicks on a category. In my case, I want to scroll the page when an index (i.e. an alphabet) at the top of the page, is clicked.


  [1]: http://www.1stwebdesigner.com/wp-content/uploads/2010/07/index.html

How to fix a Div to top of page with CSS only

`findOne()` results in pretty-print json object.

`find()` results in jarbled json object.

How can I make `find()` the same as `findOne()`, when it comes to display in the mongo shell?

In Mongo, how do I pretty-print results so .find() looks like .findOne()

I&#39;m searching a way to represent my Django project model graphically.

Is there a &quot;native&quot; way to do this kind of [ERD][1] (diagram) ?

---

Update following [@Etienne instructions](https://stackoverflow.com/a/6777376/305189)

Here is an example of how I finally view the PDF representing some models of my django project

    $ python manage.py graph_models app1 app2 ... | dot -Tpdf | evince

- It actually generates the dot data with my applications (app1, app2, ...)
- Passes the result to `dot` to output into PDF format
- Opens the output with `evince`

  [1]: http://en.wikipedia.org/wiki/Entity-relationship_model

Django - Model graphic representation (ERD)

I'm searching a way to represent my Django project model graphically.
Is there a "native" way to do this kind of <a href="http://en.wikipedia.org/wiki/Entity-relationship_model" target="_blank" rel="noopener noreferrer">ERD</a> (diagram) ?
<hr>
Update following <a href="https://stackoverflow.com/a/6777376/305189" target="_blank" rel="noopener noreferrer">@Etienne instructions</a>
Here is an example of how I finally view the PDF representing some models of my django project
<pre><code class="hljs language-ruby">$ python manage.py graph_models app1 app2 ... | dot -Tpdf | evince
</code></pre>
<ul>
<li>
It actually generates the dot data with my applications (app1, app2, ...)
</li>
<li>
Passes the result to <code>dot</code> to output into PDF format
</li>
<li>
Opens the output with <code>evince</code>
</li>
</ul>

I&#39;m writing a Django Middleware class that I want to execute only once at startup, to initialise some other arbritary code. I&#39;ve followed the very nice solution posted by sdolan [here][1], but the &quot;Hello&quot; message is output to the terminal *twice*. E.g.

    from django.core.exceptions import MiddlewareNotUsed
    from django.conf import settings
    
    class StartupMiddleware(object):
        def __init__(self):
            print &quot;Hello world&quot;
            raise MiddlewareNotUsed(&#39;Startup complete&#39;)

and in my Django settings file, I&#39;ve got the class included in the `MIDDLEWARE_CLASSES` list.

But when I run Django using runserver and request a page, I get in the terminal

    Django version 1.3, using settings &#39;config.server&#39;
    Development server is running at http://127.0.0.1:8000/
    Quit the server with CONTROL-C.
    Hello world
    [22/Jul/2011 15:54:36] &quot;GET / HTTP/1.1&quot; 200 698
    Hello world
    [22/Jul/2011 15:54:36] &quot;GET /static/css/base.css HTTP/1.1&quot; 200 0

Any ideas why &quot;Hello world&quot; is printed twice? Thanks.

  [1]: https://stackoverflow.com/questions/3495964/in-django-how-do-i-call-the-subcommand-syncdb-from-the-initialization-script

Execute code when Django starts ONCE only?

I&#39;m running django on gunicorn+nginx. I&#39;m facing a problem with file uploads. Actually uploads are working fine but gunicorn times out thus causing this in nginx:

    2011/07/25 12:13:47 [error] 15169#0: *2317 upstream timed out (110: Connection timed out) while reading response header from upstream, client: IP-ADDRESS, server: SERVER, request: &quot;GET /photos/events/event/25 HTTP/1.1&quot;, upstream: &quot;http://127.0.0.1:29000/photos/events/event/25&quot;, host: &quot;HOST&quot;, referrer: &quot;REFERER_ADDRESS&quot;

If I refresh the page, I can see all the photos are uploaded just fine. The problem is that it causes a timeout thus giving the impression that upload did not work.

here is my gunicorn conf:

    bind = &quot;127.0.0.1:29000&quot;
    logfile = &quot;/path/to/logs/gunicorn.log&quot;
    workers = 3

I tried changing timeout but it didn&#39;t work.


110: Connection timed out (Nginx/Gunicorn)

I have a Django form with a ``RegexField``, which is very similar to a normal text input field.

In my view, under certain conditions I want to hide it from the user, and trying to keep the form as similar as possible. What&#39;s the best way to turn this field into a ``HiddenInput`` field?

I know I can set attributes on the field with:

    form[&#39;fieldname&#39;].field.widget.attr[&#39;readonly&#39;] = &#39;readonly&#39;

And I can set the desired initial value with:

    form.initial[&#39;fieldname&#39;] = &#39;mydesiredvalue&#39;

However, that won&#39;t change the form of the widget.

What&#39;s the best / most &quot;django-y&quot; / least &quot;hacky&quot; way to make this field a `&lt;input type=&quot;hidden&quot;&gt;` field?

Change a Django form field to a hidden field

I&#39;m defining my Django models right now and I realized that there wasn&#39;t a `OneToManyField` in the model field types. I&#39;m sure there&#39;s a way to do this, so I&#39;m not sure what I&#39;m missing. I essentially have something like this:

    class Dude(models.Model):
        numbers = models.OneToManyField(&#39;PhoneNumber&#39;)
    
    class PhoneNumber(models.Model):
        number = models.CharField()

In this case, each `Dude` can have multiple `PhoneNumber`s, but the relationship should be unidirectional, in that I don&#39;t need to know from the `PhoneNumber` which `Dude` owns it, per se, as I might have many different objects that own `PhoneNumber` instances, such as a `Business` for example:

    class Business(models.Model):
        numbers = models.OneToManyField(&#39;PhoneNumber&#39;)

What would I replace `OneToManyField` (which doesn&#39;t exist) with in the model to represent this kind of relationship? I&#39;m coming from Hibernate/JPA where declaring a one-to-many relationship was as easy as:

    @OneToMany
    private List&lt;PhoneNumber&gt; phoneNumbers;

How can I express this in Django?  

How to express a One-To-Many relationship in Django?

I&#39;m writing a reusable django app and I need to ensure that its models are only sync&#39;ed when the app is in test mode. I&#39;ve tried to use a custom DjangoTestRunner, but I found no examples of how to do that (the documentation only shows how to define a custom test runner).

So, does anybody have an idea of how to do it?

**EDIT**

Here&#39;s how I&#39;m doing it:

    #in settings.py
    import sys
    TEST = &#39;test&#39; in sys.argv

Hope it helps.

Detect django testing mode

    rails g model Rating user_id:integer message:string value:integer


How can I completely remove this model? Thanks

Removing a model in rails (reverse of &quot;rails g model Title...&quot;)

I have basically a username is unique (case insensitive), but the case matters when displaying as provided by the user. 

I have the following requirements:

+ field is CharField compatible
+ field is unique, but case insensitive
+ field needs to be searchable ignoring case (avoid using iexact, easily forgotten)
+ field is stored with case intact 
+ preferably enforced on database level
+ preferably avoid storing an extra field

Is this possible in Django? 

The only solution I came up with is &quot;somehow&quot; override the Model manager, use an extra field, or always use &#39;iexact&#39; in searches.

I&#39;m on Django 1.3 and PostgreSQL 8.4.2.

Case insensitive unique model fields in Django?

I have a User model that has a :credits attribute.   I want a simple button that will add 5 to  the user&#39;s credits, through a route called &quot;add&quot; so that /users/3/add would add 5 to the credits of user id = 3.

  

    def add
        @user = User.find(params[:id])
        @user.credits += 5
        redirect_to root_path
    end

That is the relevant part of my controller.  The problem is, I dont want to call @user.save because I have a before_save callback that re-encrypts the user&#39;s password based on the current UTC time.   I just want to simply add 5 to the attribute and avoid the callback, I never thought such a simple thing could be so hard.

EDIT:

I changed the callback to :before_create,
here is my new controller code (relevant part):

      def add
        @user = User.find(params[:id])
        @user.add_credits(5)
        @user.save
        flash[:success] = &quot;Credits added!&quot;
        redirect_to root_path
      end

and here is my code in the model:

     def add_credits(num)
        self.credits = num
     end

EDIT 2:

Ok it was a validation problem that made the changes in &quot;EDIT&quot; not work, but I&#39;d still love an answer to the original question of updating without callbacks!

Rails: Update model attribute without invoking callbacks

So, i have a file models.py in MyApp folder:
    
    from django.db import models
    class Model_One(models.Model):
        ...
    class Model_Two(models.Model):
        ...
    ...
It can be about 10-15 classes.
**How to find all models in the MyApp and get their names?** 

Since models are not iterable, I don&#39;t know if this is even possible.

Django get list of models in application

I am confused to understand what is the meaning of this words:

`Entity`, `Model`, `DataModel`, `ViewModel`

Can any body help me to understanding them please? Thank you all.

what is difference between a Model and an Entity

I am trying to visualize my data flow with a Sankey Diagram in R.

I found [this blog post](http://biologicalposteriors.blogspot.com/2010/07/sankey-diagrams-in-r.html) linking to an R script that produces a Sankey Diagram; unfortunately, it&#39;s quite raw and somewhat limited (see below for sample code and data).

Does anyone know of other scripts—or maybe even a package—that is more developed? My end goal is to visualize both data flow and percentages by relative size of diagram components, like in [these  examples of Sankey Diagrams](http://www.sankey-diagrams.com/tag/software/). 

I posted [a somewhat similar question on the r-help list](http://tolstoy.newcastle.edu.au/R/e17/help/12/03/7682.html), but after two weeks without any responses I&#39;m trying my luck here on stackoverflow.

Thanks,
Eric

PS. I&#39;m aware of the [Parallel Sets Plot](https://stats.stackexchange.com/questions/12029/is-it-possible-to-create-parallel-sets-plot-using-r), but that is not what I&#39;m looking for.

    # thanks to, https://tonybreyal.wordpress.com/2011/11/24/source_https-sourcing-an-r-script-from-github/
      sourc.https     &lt;- function(url, ...) {
    # install and load the RCurl package 
    if (match(&#39;RCurl&#39;, nomatch=0, installed.packages()[,1])==0) {
      install.packages(c(&quot;RCurl&quot;), dependencies = TRUE)
      require(RCurl)  
    } else require(RCurl)    

    # parse and evaluate each .R script
      sapply(c(url, ...), function(u) {
        eval(parse(text = getURL(u, followlocation = TRUE, 
        cainfo  = system.file(&quot;CurlSSL&quot;, &quot;cacert.pem&quot;, 
        package = &quot;RCurl&quot;))), envir = .GlobalEnv)
     } )
     }
    
    # from https://gist.github.com/1423501
    sourc.https(&quot;https://raw.github.com/gist/1423501/55b3c6f11e4918cb6264492528b1ad01c429e581/Sankey.R&quot;)
    
    # My example (there is another example inside Sankey.R):
    inputs = c(6, 144)
    losses = c(6,47,14,7, 7, 35, 34)
    unit = &quot;n =&quot;
    
    labels = c(&quot;Transfers&quot;,
               &quot;Referrals\n&quot;,
               &quot;Unable to Engage&quot;,
               &quot;Consultation only&quot;,
               &quot;Did not complete the intake&quot;,
               &quot;Did not engage in Treatment&quot;,
               &quot;Discontinued Mid-Treatment&quot;,
               &quot;Completed Treatment&quot;,
               &quot;Active in \nTreatment&quot;)
    
    SankeyR(inputs,losses,unit,labels)
    
    # Clean up my mess
    rm(&quot;inputs&quot;, &quot;labels&quot;, &quot;losses&quot;, &quot;SankeyR&quot;, &quot;sourc.https&quot;, &quot;unit&quot;)

Sankey Diagram produced with the above code, ![Sankey Diagram produced with the code above][1]

  [1]: http://i.stack.imgur.com/9jiMq.png

Sankey Diagrams in R?

Is there a simple online tool that will generate a dependency graph (boxes linked by arrow lines) based on text input like: 

A -&gt; B

Much like this one:

[www.websequencediagrams.com][1]

(It generates a sequence diagram)


  [1]: http://www.websequencediagrams.com

Content Type	Original Author	Original Content on Stackoverflow
Question	Pierre de LESPINAY	View Question on Stackoverflow
Solution 1 - Django	Etienne	View Answer on Stackoverflow
Solution 2 - Django	Samuele Mattiuzzo	View Answer on Stackoverflow

Django - Model graphic representation (ERD)

Django Problem Overview

Django Solutions

Solution 1 - Django

Solution 2 - Django

In Mongo, how do I pretty-print results so .find() looks like .findOne()

How to fix a Div to top of page with CSS only

Attributions