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  • Django model: Reference foreign key table in __unicode__ function for admin

    - by pa
    Example models: class Parent(models.Model): name = models.CharField() def __unicode__(self): return self.name class Child(models.Model): parent = models.ForeignKey(Parent) def __unicode__(self): return self.parent.name # Would reference name above I'm wanting the Child.unicode to refer to Parent.name, mostly for the admin section so I don't end up with "Child object" or similar, I'd prefer to display it more like "Child of ". Is this possible? Most of what I've tried hasn't worked unfortunately.

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  • how to count all distinct records in many-to-many relations in django ORM?

    - by marduk-pl
    hi, i have two models: class Project(models.Model): categories = models.ManyToManyField(Category) class Category(models.Model): name = models.CharField() now, i make some queryset: query = Project.objects.filter(id__in=[1,2,3,4]) and i like to get list of all distinct categories in this queryset with count of projects with refering to these categories - exactly i would like to get that results: category1 - 10 projects category2 - 5 projects that is opposite to this query: query2 = query.annotate(Count('categories')) what return me: project1 - 2categories project2 - 7categories how can i make it in django ORM?

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  • get average from set of objects in django

    - by dotty
    Hay, i have a simple rating system for a property. You give it a mark out of 5 (stars). The models are defined like this def Property(models.Model) # stuff here def Rating(models.Model) property = models.ForeignKey(Property) stars = models.IntegerField() What i want to do is get a property, find all the Rating objects, collect them, then get the average 'stars' from them. any ideas how to do this?

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  • ahow can I resolve Django Error: str' object has no attribute 'autoescape'?

    - by Angelbit
    Hi have tried to create a inclusion tag on Django but don't work and return str' object has no attribute 'autoescape' this is the code of custom tag: from django import template from quotes.models import Quotes register = template.Library() def show_quote(): quote = Quotes.objects.values('quote', 'author').get(id=0) return {'quote': quote['quote']} register.inclusion_tag('quotes.html')(show_quote) EDIT: Quote class from django.db import models class Quotes(models.Model): quote = models.CharField(max_length=255) author = models.CharField(max_length=100) class Meta: db_table = 'quotes' quotes.html <blockquote id="quotes">{{ quote }}</blockquote>

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  • Can this django query be improved?

    - by Hobhouse
    Given a model structure like this: class Book(models.Model): user = models.ForeignKey(User) class Readingdate(models.Model): book = models.ForeignKey(Book) date = models.DateField() One book may have several readingdates. How do I list books having at least one readingdate within a specific year? I can do this: from_date = datetime.date(2010,1,1) to_date = datetime.date(2010,12,31) book_ids = Readingdate.objects\ .filter(date__range=(from_date,to_date))\ .values_list('book_id', flat=True) books_read_2010 = Book.objects.filter(id__in=book_ids) Is it possible to do this with one queryset, or is this the best way?

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  • Django database - how to add this column in raw SQL.

    - by alex
    Suppose I have my models set up already. class books(models.Model): title = models.CharField... ISBN = models.Integer... What if I want to add this column to my table? user = models.ForeignKey(User, unique=True) How would I write the raw SQL in my database so that this column works?

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  • IntegrityError with Booleand Fields and Postgresql

    - by xRobot
    I have this simple Blog model: class Blog(models.Model): title = models.CharField(_('title'), max_length=60, blank=True, null=True) body = models.TextField(_('body')) user = models.ForeignKey(User) is_public = models.BooleanField(_('is public'), default = True) When I insert a blog in admin interface, I get this error: IntegrityError at /admin/blogs/blog/add/ null value in column "is_public" violates not-null constraint Why ???

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  • How Do You Actually Model Data?

    Since the 1970’s Developers, Analysts and DBAs have been able to represent concepts and relations in the form of data through the use of generic symbols.  But what is data modeling?  The first time I actually heard this term I could not understand why anyone would want to display a computer on a fashion show runway. Hey, what do you expect? At that time I was a freshman in community college, and obviously this was a long time ago.  I have since had the chance to learn what data modeling truly is through using it. Data modeling is a process of breaking down information and/or requirements in to common categories called objects. Once objects start being defined then relationships start to form based on dependencies found amongst other existing objects.  Currently, there are several tools on the market that help data designer actually map out objects and their relationships through the use of symbols and lines.  These diagrams allow for designs to be review from several perspectives so that designers can ensure that they have the optimal data design for their project and that the design is flexible enough to allow for potential changes and/or extension in the future. Additionally these basic models can always be further refined to show different levels of details depending on the target audience through the use of three different types of models. Conceptual Data Model(CDM)Conceptual Data Models include all key entities and relationships giving a viewer a high level understanding of attributes. Conceptual data model are created by gathering and analyzing information from various sources pertaining to a project during the typical planning phase of a project. Logical Data Model (LDM)Logical Data Models are conceptual data models that have been expanded to include implementation details pertaining to the data that it will store. Additionally, this model typically represents an origination’s business requirements and business rules by defining various attribute data types and relationships regarding each entity. This additional information can be directly translated to the Physical Data Model which reduces the actual time need to implement it. Physical Data Model(PDMs)Physical Data Model are transformed Logical Data Models that include the necessary tables, columns, relationships, database properties for the creation of a database. This model also allows for considerations regarding performance, indexing and denormalization that are applied through database rules, data integrity. Further expanding on why we actually use models in modern application/database development can be seen in the benefits that data modeling provides for data modelers and projects themselves, Benefits of Data Modeling according to Applied Information Science Abstraction that allows data designers remove concepts and ideas form hard facts in the form of data. This gives the data designers the ability to express general concepts and/or ideas in a generic form through the use of symbols to represent data items and the relationships between the items. Transparency through the use of data models allows complex ideas to be translated in to simple symbols so that the concept can be understood by all viewpoints and limits the amount of confusion and misunderstanding. Effectiveness in regards to tuning a model for acceptable performance while maintaining affordable operational costs. In addition it allows systems to be built on a solid foundation in terms of data. I shudder at the thought of a world without data modeling, think about it? Data is everywhere in our lives. Data modeling allows for optimizing a design for performance and the reduction of duplication. If one was to design a database without data modeling then I would think that the first things to get impacted would be database performance due to poorly designed database and there would be greater chances of unnecessary data duplication that would also play in to the excessive query times because unneeded records would need to be processed. You could say that a data designer designing a database is like a box of chocolates. You will never know what kind of database you will get until after it is built.

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  • Disable touch pad for mouse button region on new HP pavillion models?

    - by John
    i bought a new hp pavillion dv6 series laptop. the laptop itself is fine but it has the new hp touchpad mouse which i absolutely hate. its such a stupid problem to have with a computer. the left and right mouse buttons are, themselves, part of of the touchpad, meaning that if i tap the buttons without actually pressing them down, it registers the same way as the mouse pad (the cursor moves, tap to click activates, etc.) this is a major annoyance because it prevents you from operating the mouse pad with anything more than a single finger; if for example i use my right hand index finger to move the cursor using the touch pad and rest my left hand index finger on the left mouse button for more efficient mouse-ing, the mouse will react as if im trying to use 2 fingers to move it and it will either just sit there or will spaz out. the only way this works is if i keep the finger that is resting on the mouse button absolutely still, which is very difficult and, therefore, very annoying. also, even if i do abide by the arbitrary new decree of single-finger mousepad operation, i still have a problem because when i press down on the left or right click buttons, the mouse moves slightly, what with the buttons also being part of the touch pad and all. this would not be that hard to avoid except that they decided to also make the buttons much harder to press down. now whenever i go to click something, i press hard on the mouse button, causing my finger to slightly move or roll or flatten out a bit, causing the cursor to move slightly, and causing me to click on something different. what i would like to know is if there is anyway that i can disable the touch pad on the buttons. i have gone through all of the settings under the synaptics menus but i cannot find anything about this. did i miss something in one of the menus? if not, then are there any updated drivers that allow for toggling of this function?

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  • Strategies for avoiding SQL in your Controllers... or how many methods should I have in my Models?

    - by Keith Palmer
    So a situation I run into reasonably often is one where my models start to either: Grow into monsters with tons and tons of methods OR Allow you to pass pieces of SQL to them, so that they are flexible enough to not require a million different methods For example, say we have a "widget" model. We start with some basic methods: get($id) insert($record) update($id, $record) delete($id) getList() // get a list of Widgets That's all fine and dandy, but then we need some reporting: listCreatedBetween($start_date, $end_date) listPurchasedBetween($start_date, $end_date) listOfPending() And then the reporting starts to get complex: listPendingCreatedBetween($start_date, $end_date) listForCustomer($customer_id) listPendingCreatedBetweenForCustomer($customer_id, $start_date, $end_date) You can see where this is growing... eventually we have so many specific query requirements that I either need to implement tons and tons of methods, or some sort of "query" object that I can pass to a single -query(query $query) method... ... or just bite the bullet, and start doing something like this: list = MyModel-query(" start_date X AND end_date < Y AND pending = 1 AND customer_id = Z ") There's a certain appeal to just having one method like that instead of 50 million other more specific methods... but it feels "wrong" sometimes to stuff a pile of what's basically SQL into the controller. Is there a "right" way to handle situations like this? Does it seem acceptable to be stuffing queries like that into a generic -query() method? Are there better strategies?

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  • Method for defining simultaneous has-many and has-one associations between two models in CakePHP?

    - by Hobonium
    One thing with which I have long had problems, within the CakePHP framework, is defining simultaneous hasOne and hasMany relationships between two models. For example: BlogEntry hasMany Comment BlogEntry hasOne MostRecentComment (where MostRecentComment is the Comment with the most recent created field) Defining these relationships in the BlogEntry model properties is problematic. CakePHP's ORM implements a has-one relationship as an INNER JOIN, so as soon as there is more than one Comment, BlogEntry::find('all') calls return multiple results per BlogEntry. I've worked around these situations in the past in a few ways: Using a model callback (or, sometimes, even in the controller or view!), I've simulated a MostRecentComment with: $this->data['MostRecentComment'] = $this->data['Comment'][0]; This gets ugly fast if, say, I need to order the Comments any way other than by Comment.created. It also doesn't Cake's in-built pagination features to sort by MostRecentComment fields (e.g. sort BlogEntry results reverse-chronologically by MostRecentComment.created. Maintaining an additional foreign key, BlogEntry.most_recent_comment_id. This is annoying to maintain, and breaks Cake's ORM: the implication is BlogEntry belongsTo MostRecentComment. It works, but just looks...wrong. These solutions left much to be desired, so I sat down with this problem the other day, and worked on a better solution. I've posted my eventual solution below, but I'd be thrilled (and maybe just a little mortified) to discover there is some mind-blowingly simple solution that has escaped me this whole time. Or any other solution that meets my criteria: it must be able to sort by MostRecentComment fields at the Model::find level (ie. not just a massage of the results); it shouldn't require additional fields in the comments or blog_entries tables; it should respect the 'spirit' of the CakePHP ORM. (I'm also not sure the title of this question is as concise/informative as it could be.)

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  • What makes people think that NNs have more computational power than existing models?

    - by Bubba88
    I've read in Wikipedia that neural-network functions defined on a field of arbitrary real/rational numbers (along with algorithmic schemas, and the speculative `transrecursive' models) have more computational power than the computers we use today. Of course it was a page of russian wikipedia (ru.wikipedia.org) and that may be not properly proven, but that's not the only source of such.. rumors Now, the thing that I really do not understand is: How can a string-rewriting machine (NNs are exactly string-rewriting machines just as Turing machines are; only programming language is different) be more powerful than a universally capable U-machine? Yes, the descriptive instrument is really different, but the fact is that any function of such class can be (easily or not) turned to be a legal Turing-machine. Am I wrong? Do I miss something important? What is the cause of people saying that? I do know that the fenomenum of undecidability is widely accepted today (though not consistently proven according to what I've read), but I do not really see a smallest chance of NNs being able to solve that particular problem. Add-in: Not consistently proven according to what I've read - I meant that you might want to take a look at A. Zenkin's (russian mathematician) papers after mid-90-s where he persuasively postulates the wrongness of G. Cantor's concepts, including transfinite sets, uncountable sets, diagonalization method (method used in the proof of undecidability by Turing) and maybe others. Even Goedel's incompletness theorems were proven in right way in only 21-st century.. That's all just to plug Zenkin's work to the post cause I don't know how widespread that knowledge is in CS community so forgive me if that did look stupid. Thank you!

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  • How do I find the .max of an attribute value among a group of different Models?

    - by Angela
    Hi, everyone: I am also open to just straight-up refactoring what I'm finding to be pretty repetitive, but to give a baseline of how it's working.... I have for every contact a Campaign, which has_many of three types of Models: Email, Call, and Letter. When an Email (Call or Letter) has been executed for a specific contact, I have a Contact_Email(_or_Call_or_Letter) which belongs to both the Contact and the Model (Email_or_Call_or_Letter). Each Contact_Email for example pairing has a :date_sent attribute. So does each Contact_Call and Contact_Letter. How do I find the latest of all of them? Here is the code I wrote that can find the latest Email and my finding retyping similar code for Call and Letter, but then stuck on how to do a .max on all of them: def last_email(contact) #get campaign the contact belongs to @campaign = Campaign.find_by_id(contact.campaign_id) @last_email = ContactEmail.find(:last, :conditions => "contact_id = #{contact.id}", :order => "date_sent DESC") @last_call = ContactCall.find(:last, :conditions => "contact_id = #{contact.id}", :order => "date_sent DESC") @last_letter = ContactLetter.find(:last, :conditions => "contact_id = #{contact.id}", :order => "date_sent DESC") # how do I get the latest of all of these to display? if @last_sent_email.nil? return "no email sent" else return @last_sent_email.date_sent end end Question 1: With what I have, how can I find effectively @last_event given I can find the last Email, last Call, and last Letter for every contact? Question 2: How can I remove the repetitive code that I have to write for each Model?

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  • How do I Order on common attribute of two models in the DB?

    - by Will
    If i have two tables Books, CDs with corresponding models. I want to display to the user a list of books and CDs. I also want to be able to sort this list on common attributes (release date, genre, price, etc.). I also have basic filtering on the common attributes. The list will be large so I will be using pagination in manage the load. items = [] items << CD.all(:limit => 20, :page => params[:page], :order => "genre ASC") items << Book.all(:limit => 20, :page => params[:page], :order => "genre ASC") re_sort(items,"genre ASC") Right now I am doing two queries concatenating them and then sorting them. This is very inefficient. Also this breaks down when I use paging and filtering. If I am on page 2 of how do I know what page of each table individual table I am really on? There is no way to determine this information without getting all items from each table. I have though that if I create a new Class called items that has a one to one relationship with either a Book or CD and do something like Item.all(:limit => 20, :page => params[:page], :include => [:books, :cds], :order => "genre ASC") However this gives back an ambiguous error. So can only be refined as Item.all(:limit => 20, :page => params[:page], :include => [:books, :cds], :order => "books.genre ASC") And does not interleave the books and CDs in a way that I want. Any suggestions.

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  • In Java, is there a gain in using interfaces for complex models?

    - by Gnoupi
    The title is hardly understandable, but I'm not sure how to summarize that another way. Any edit to clarify is welcome. I have been told, and recommended to use interfaces to improve performances, even in a case which doesn't especially call for the regular "interface" role. In this case, the objects are big models (in a MVC meaning), with many methods and fields. The "good use" that has been recommended to me is to create an interface, with its unique implementation. There won't be any other class implementing this interface, for sure. I have been told that this is better to do so, because it "exposes less" (or something close) to the other classes which will use methods from this class, as these objects are referring to the object from its interface (all public method from the implementation being reproduced in the interface). This seems quite strange to me, as it seems like a C++ use to me (with header files). There I see the point, but in Java? Is there really a point in making an interface for such unique implementation? I would really appreciate some clarifications on the topic, so I could justify not following such kind of behavior, and the hassle it creates from duplicating all declarations.

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  • In Java, is there a performance gain in using interfaces for complex models?

    - by Gnoupi
    The title is hardly understandable, but I'm not sure how to summarize that another way. Any edit to clarify is welcome. I have been told, and recommended to use interfaces to improve performances, even in a case which doesn't especially call for the regular "interface" role. In this case, the objects are big models (in a MVC meaning), with many methods and fields. The "good use" that has been recommended to me is to create an interface, with its unique implementation. There won't be any other class implementing this interface, for sure. I have been told that this is better to do so, because it "exposes less" (or something close) to the other classes which will use methods from this class, as these objects are referring to the object from its interface (all public methods from the implementation being reproduced in the interface). This seems quite strange to me, as it seems like a C++ use to me (with header files). There I see the point, but in Java? Is there really a point in making an interface for such unique implementation? I would really appreciate some clarifications on the topic, so I could justify not following such kind of behavior, and the hassle it creates from duplicating all declarations. Edit: Plenty of valid points in most answers, I'm wondering if I won't switch this question for a community wiki, so we can regroup these points in more structured answers.

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  • How can I add two models in one form, where one model is a has_many :through?

    - by Angela
    How do I model having multiple Addresses for a Company and assign a single Address to a Contact? Contacts belong_to a Company. A Company has_many Contacts. A Company also has_many Addresses. And each Contact has_one Address. I want to be able, whenever I create a New Contact, to access all the addresses in all Contacts that belong to the Company. Here is are my Models: class Company < ActiveRecord::Base attr_accessible :name, :phone, :addresses has_many :contacts has_many :addresses, :through => :contacts end class Contact < ActiveRecord::Base attr_accessible :first_name, :last_name, :title, :phone, :fax, :email, :company, :date_entered, :campaign_id, :company_name, :address belongs_to :company has_one :address accepts_nested_attributes_for :address end class Address < ActiveRecord::Base attr_accessible :street1 has_many :contacts end How do I create the View in the _form for Contacts so that I can 1) Add an Address when creating a Contact; 2) Display the options of the Address. Here is how I am doing step 1, which is just to add a new address for a new contact: <% f.fields_for :addresses do |builder| %> <p> <%= builder.label :street1, "Street 1" %> </br> <%= builder.text_field :street1 %> <p> Right now, what I have doesn't work. The console says I cannot mass-assign addresses when I hit "submit" on this New contact form.

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  • How important is it that models be consistent across project components?

    - by RonLugge
    I have a project with two components, a server-side component and a client-side component. For various reasons, the client-side device doesn't carry a fully copy of the database around. How important is it that my models have a 1:1 correlation between the two sides? And, to extend the question to my bigger concern, are there any time-bombs I'm going to run into down the line if they don't? I'm not talking about having different information on each side, but rather the way the information is encapsulated will vary. (Obviously, storage mechanisms will also vary) The server side will store each user, each review, each 'item' with seperate tables, and create links between them to gather data as necessary. The client side shouldn't have a complete user database, however, so rather than link against the user for gathering things like 'name', I'd store that on the review. In other words... --- Server Side --- Item: +id //Store stuff about the item User: +id +Name -Password Review: +id +itemId +rating +text +userId --- Device Side --- Item: +id +AverageRating Review: +id +rating +text +userId +name User: +id +Name //Stuff The basic idea is that certain 'critical' information gets moved one level 'up'. A user gets the list of 'items' relevant to their query, with certain review-orientation moved up (i. e. average rating). If they want more info, they query the detail view for the item, and the actual reviews get queried and added to the dataset (and displayed). If they query the actual review, the review gets queried and they pick up some additional user info along the way (maybe; I'm not sure if the user would have any use for any of the additional user information). My basic concern is that I don't wan't to glut the user's bandwidth or local storage with a huge variety of information that they just don't need, even if proper database normalizations suggests that information REALLY should be stored at a 'lower' level. I've phrased this as a fairly low-level conceptual issue because that's the level I'm trying to think / worry over, but if it matters I'm creating a PHP / MySQL server that provides data for a iOS / CoreData client.

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  • How can I have a single helper work on different models passed to it?

    - by Angela
    I am probably going to need to refactor in two steps since I'm still developing the project and learning the use-cases as I go along since it is to scratch my own itch. I have three models: Letters, Calls, Emails. They have some similarilty, but I anticipate they also will have some different attributes as you can tell from their description. Ideally I could refactor them as Events, with a type as Letters, Calls, Emails, but didn't know how to extend subclasses. My immediate need is this: I have a helper which checks on the status of whether an email (for example) was sent to a specific contact: def show_email_status(contact, email) @contact_email = ContactEmail.find(:first, :conditions => {:contact_id => contact.id, :email_id => email.id }) if ! @contact_email.nil? return @contact_email.status end end I realized that I, of course, want to know the status for whether a call was made to a contact as well, so I wrote: def show_call_status(contact, call) @contact_call = ContactCall.find(:first, :conditions => {:contact_id => contact.id, :call_id => call.id }) if ! @contact_call.nil? return @contact_call.status end end I would love to be able to just have a single helper show_status where I can say show_status(contact,call) or show_status(contact,email) and it would know whether to look for the object @contact_call or @contact_email. Yes, it would be easier if it were just @contact_event, but I want to do a small refactoring while I get the program up and running, and this would make the ability to do a history for a given contact much easier. Thanks!

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  • Why do I get 'Connection refused - connect(2)' for some models?

    - by Will
    I have a rails application running for the past 90 days that suddenly stopped working. Debugging the problem I found that I can read from the DB but not write to it. At least for certain models. There is one model that I can save whereas all others return Connection refused - connect(2) when I attempt to save them. They all used to work fine last month. I have no idea how to determine what the problem may be. Unfortunately I do not have access to the actual server remotely right now so I am limited in my debugging ability. I was able to get some non-tech people to run simple commands though that may help identify my problem. I will also be getting access tomorrow at some point. 1 Check from the console ./script/console >> a = Post.last.clone => #<Post id: nil, title: "test"... >> a.ex_id = 7 >> a.save Connection refused - connect(2) ... ... >> b = Story.last.console => #<Story id: nil, title: "test"... >> a.ex_id = 7 >> a.save => true I am not sure why this works for story and not post. This is consistent over many tests. 2 Check from mysql ./script/dbconsole -p mysql> INSERT INTO Posts (`title`,`body`, `ex_id`) SELECT `title`, `body`, 7 FROM Posts WHERE ID = 1; Query OK, 1 row affected (0.01 sec) Records: 1 Duplicates: 0 Warnings: 0 And as you can see I am able to write to the table with the same credientials that Rails uses? Does anyone know why I get connection refused in the console?

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  • PyDev and Django: PyDev breaking Django shell?

    - by Rosarch
    I've set up a new project, and populated it with simple models. (Essentially I'm following the tut.) When I run python manage.py shell on the command line, it works fine: >python manage.py shell Python 2.6.4 (r264:75708, Oct 26 2009, 08:23:19) [MSC v.1500 32 bit (Intel)] on win32 Type "help", "copyright", "credits" or "license" for more information. (InteractiveConsole) >>> from mysite.myapp.models import School >>> School.objects.all() [] Works great. Then, I try to do the same thing in Eclipse (using a Django project that is composed of the same files.) Right click on mysite project Django Shell with Django environment This is the output from the PyDev Console: >>> import sys; print('%s %s' % (sys.executable or sys.platform, sys.version)) C:\Python26\python.exe 2.6.4 (r264:75708, Oct 26 2009, 08:23:19) [MSC v.1500 32 bit (Intel)] >>> >>> from django.core import management;import mysite.settings as settings;management.setup_environ(settings) 'path\\to\\mysite' >>> from mysite.myapp.models import School >>> School.objects.all() Traceback (most recent call last): File "<console>", line 1, in <module> File "C:\Python26\lib\site-packages\django\db\models\query.py", line 68, in __repr__ data = list(self[:REPR_OUTPUT_SIZE + 1]) File "C:\Python26\lib\site-packages\django\db\models\query.py", line 83, in __len__ self._result_cache.extend(list(self._iter)) File "C:\Python26\lib\site-packages\django\db\models\query.py", line 238, in iterator for row in self.query.results_iter(): File "C:\Python26\lib\site-packages\django\db\models\sql\query.py", line 287, in results_iter for rows in self.execute_sql(MULTI): File "C:\Python26\lib\site-packages\django\db\models\sql\query.py", line 2368, in execute_sql cursor = self.connection.cursor() File "C:\Python26\lib\site-packages\django\db\backends\__init__.py", line 81, in cursor cursor = self._cursor() File "C:\Python26\lib\site-packages\django\db\backends\sqlite3\base.py", line 170, in _cursor self.connection = Database.connect(**kwargs) OperationalError: unable to open database file What am I doing wrong here?

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  • Which Code Should Go Where in MVC Structure

    - by Oguz
    My problem is in somewhere between model and controller.Everything works perfect for me when I use MVC just for crud (create, read, update, delete).I have separate models for each database table .I access these models from controller , to crud them . For example , in contacts application,I have actions (create, read, update, delete) in controller(contact) to use model's (contact) methods (create, read, update, delete). The problem starts when I try to do something more complicated. There are some complex processes which I do not know where should I put them. For example , in registering user process. I can not just finish this process in user model because , I have to use other models too (sending mails , creating other records for user via other models) and do lots of complex validations via other models. For example , in some complex searching processes , I have to access lots of models (articles, videos, images etc.) Or, sometimes , I have to use apis to decide what I will do next or which database model I will use to record data So where is the place to do this complicated processes. I do not want to do them in controllers , Because sometimes I should use these processes in other controllers too. And I do not want to put these process in models because , I use models as database access layers .May be I am wrong,I want to know . Thank you for your answer .

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  • Dynamically setting the queryset of a ModelMultipleChoiceField to a custom recordset

    - by Daniel Quinn
    I've seen all the howtos about how you can set a ModelMultipleChoiceField to use a custom queryset and I've tried them and they work. However, they all use the same paradigm: the queryset is just a filtered list of the same objects. In my case, I'm trying to get the admin to draw a multiselect form that instead of using usernames as the text portion of the , I'd like to use the name field from my account class. Here's a breakdown of what I've got: # models.py class Account(models.Model): name = models.CharField(max_length=128,help_text="A display name that people understand") user = models.ForeignKey(User, unique=True) # Tied to the User class in settings.py class Organisation(models.Model): administrators = models.ManyToManyField(User) # admin.py from django.forms import ModelMultipleChoiceField from django.contrib.auth.models import User class OrganisationAdminForm(forms.ModelForm): def __init__(self, *args, **kwargs): from ethico.accounts.models import Account self.base_fields["administrators"] = ModelMultipleChoiceField( queryset=User.objects.all(), required=False ) super(OrganisationAdminForm, self).__init__(*args, **kwargs) class Meta: model = Organisation This works, however, I want queryset above to draw a selectbox with the Account.name property and the User.id property. This didn't work: queryset=Account.objects.all().order_by("name").values_list("user","name") It failed with this error: 'tuple' object has no attribute 'pk' I figured that this would be easy, but it's turned into hours of dead-ends. Anyone care to shed some light?

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