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  • SQLAlchemy unsupported type error - and table design issues?

    - by Az
    Hi there, back again with some more SQLAlchemy shenanigans. Let me step through this. My table is now set up as so: engine = create_engine('sqlite:///:memory:', echo=False) metadata = MetaData() students_table = Table('studs', metadata, Column('sid', Integer, primary_key=True), Column('name', String), Column('preferences', Integer), Column('allocated_rank', Integer), Column('allocated_project', Integer) ) metadata.create_all(engine) mapper(Student, students_table) Fairly simple, and for the most part I've been enjoying the ability to query almost any bit of information I want provided I avoid the error cases below. The class it is mapped from is: class Student(object): def __init__(self, sid, name): self.sid = sid self.name = name self.preferences = collections.defaultdict(set) self.allocated_project = None self.allocated_rank = 0 def __repr__(self): return str(self) def __str__(self): return "%s %s" %(self.sid, self.name) Explanation: preferences is basically a set of all the projects the student would prefer to be assigned. When the allocation algorithm kicks in, a student's allocated_project emerges from this preference set. Now if I try to do this: for student in students.itervalues(): session.add(student) session.commit() It throws two errors, one for the allocated_project column (seen below) and a similar error for the preferences column: sqlalchemy.exc.InterfaceError: (InterfaceError) Error binding parameter 4 - probably unsupported type. u'INSERT INTO studs (sid, name, allocated_rank, allocated_project) VALUES (?, ?, ?, ?, ?, ?, ?)' [1101, 'Muffett,M.', 1, 888 Human-spider relationships (Supervisor id: 123)] If I go back into my code I find that, when I'm copying the preferences from the given text files, it actually refers to the Project class which is mapped to a dictionary, using the unique project id's (pid) as keys. Thus, as I iterate through each student via their rank and to the preferences set, it adds not a project id, but the reference to the project id from the projects dictionary. students[sid].preferences[int(rank)].add(projects[int(pid)]) Now this is very useful to me since I can find out all I want to about a student's preferred projects without having to run another check to pull up information about the project id. The form you see in the error has the object print information passed as: return "%s %s (Supervisor id: %s)" %(self.proj_id, self.proj_name, self.proj_sup) My questions are: I'm trying to store an object in a database field aren't I? Would the correct way then, be copying the project information (project id, name, etc) into its own table, referenced by the unique project id? That way I can just have the project id field for one of the student tables just be an integer id and when I need more information, just join the tables? So and so forth for other tables? If the above makes sense, then how does one maintain the relationship with a column of information in one table which is a key index on another table? Does this boil down into a database design problem? Are there any other elegant ways of accomplishing this? Apologies if this is a very long-winded question. It's rather crucial for me to solve this, so I've tried to explain as much as I can, whilst attempting to show that I'm trying (key word here sadly) to understand what could be going wrong.

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  • How to extend models of other applications in Django?

    - by culebrón
    I have a small app with Category model and want to make a required foreign key referencing it from Photologue Gallery model. What's the right approach? I can make many-to-many field in Category, but this way it will not be required in Gallery. Use "register" and modify the Gallery model? Inherit it in my app?

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  • Problem bounding name to a class in Django

    - by martinthenext
    Hello! I've got a view function that has to decide which form to use depending on some conditions. The two forms look like that: class OpenExtraForm(forms.ModelForm): class Meta: model = Extra def __init__(self, *args, **kwargs): super(OpenExtraForm, self).__init__(*args, **kwargs) self.fields['opening_challenge'].label = "lame translation" def clean_opening_challenge(self): challenge = self.cleaned_data['opening_challenge'] if challenge is None: raise forms.ValidationError('??????? ???, ??????????? ?????? ???. ???????????') return challenge class HiddenExtraForm(forms.ModelForm): class Meta: model = Extra exclude = ('opening_challenge') def __init__(self, *args, **kwargs): super(HiddenExtraForm, self).__init__(*args, **kwargs) The view code goes like that: @login_required def manage_extra(request, extra_id=None, hidden=False): if not_admin(request.user): raise Http404 if extra_id is None: # Adding a new extra extra = Extra() if hidden: FormClass = HiddenExtraForm else: FormClass = OpenExtraForm else: # Editing an extra extra = get_object_or_404(Extra, pk=extra_id) if extra.is_hidden(): FromClass = HiddenExtraForm else: FormClass = OpenExtraForm if request.POST: form = FormClass(request.POST, instance=extra) if form.is_valid(): form.save() return HttpResponseRedirect(reverse(view_extra, args=[extra.id])) else: form = FormClass(instance=extra) return render_to_response('form.html', { 'form' : form, }, context_instance=RequestContext(request) ) The problem is somehow if extra.is_hidden() returns True, the statement FromClass = HiddenExtraForm doesn't work. I mean, in all other conditions that are used in the code it works fine: the correct Form classes are intantiated and it all works. But if extra.is_hidden(), the debugger shows that the condition is passed and it goes to the next line and does nothing! As a result I get a UnboundLocalVar error which says FormClass hasn't been asssigned at all. Any ideas on what's happening?

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  • Joining different models in Django

    - by Andrew Roberts
    Let's say I have this data model: class Workflow(models.Model): ... class Command(models.Model): workflow = models.ForeignKey(Workflow) ... class Job(models.Model): command = models.ForeignKey(Command) ... Suppose somewhere I want to loop through all the Workflow objects, and for each workflow I want to loop through its Commands, and for each Command I want to loop through each Job. Is there a way to structure this with a single query? That is, I'd like Workflow.objects.all() to join in its dependent models, so I get a collection that has dependent objects already cached, so workflows[0].command_set.get() doesn't produce an additional query. Is this possible?

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  • problem with pasting image over lines in wx DC

    - by Moayyad Yaghi
    hello .. i have the same code as wx Doodle pad in the wx demos i added a tool to paste images from the clipboard to the pad. using wx.DrawBitmap() function , but whenever i refresh the buffer .and call funtions ( drawSavedLines and drawSavedBitmap) it keeps putting bitmap above line no matter what i did even if i called draw bitmap first and then draw lines . is there anyway to put a line above the bitmap ? please inform me if i miss anything thanx in advance

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  • Content-Length header not returned from Pylons response

    - by Evgeny
    I'm still struggling to Stream a file to the HTTP response in Pylons. In addition to the original problem, I'm finding that I cannot return the Content-Length header, so that for large files the client cannot estimate how long the download will take. I've tried response.content_length = 12345 and I've tried response.headers['Content-Length'] = 12345 In both cases the HTTP response (viewed in Fiddler) simply does not contain the Content-Length header. How do I get Pylons to return this header? (Oh, and if you have any ideas on making it stream the file please reply to the original question - I'm all out of ideas there.)

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  • Django Grouping Query

    - by Matt
    I have the following (simplified) models: class Donation(models.Model): entry_date = models.DateTimeField() class Category(models.Model): name = models.CharField() class Item(models.Model): donation = models.ForeignKey(Donation) category = models.ForeignKey(Category) I'm trying to display the total number of items, per category, grouped by the donation year. I've tried this: Donation.objects.extra(select={'year': "django_date_trunc('year', %s.entry_date)" % Donation._meta.db_table}).values('year', 'item__category__name').annotate(items=Sum('item__quantity')) But I get a Field Error on item__category__name. I've also tried: Item.objects.extra(select={"year": "django_date_trunc('year', entry_date)"}, tables=["donations_donation"]).values("year", "category__name").annotate(items=Sum("quantity")).order_by() Which generally gets me what I want, but the item quantity count is multiplied by the number of donation records. Any ideas? Basically I want to display this: 2010 - Category 1: 10 items - Category 2: 17 items 2009 - Category 1: 5 items - Category 3: 8 items

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  • Avoiding nesting two for loops

    - by chavanak
    Hi, Please have a look at the code below: import string from collections import defaultdict first_complex=open( "residue_a_chain_a_b_backup.txt", "r" ) first_complex_lines=first_complex.readlines() first_complex_lines=map( string.strip, first_complex_lines ) first_complex.close() second_complex=open( "residue_a_chain_a_c_backup.txt", "r" ) second_complex_lines=second_complex.readlines() second_complex_lines=map( string.strip, second_complex_lines ) second_complex.close() list_1=[] list_2=[] for x in first_complex_lines: if x[0]!="d": list_1.append( x ) for y in second_complex_lines: if y[0]!="d": list_2.append( y ) j=0 list_3=[] list_4=[] for a in list_1: pass for b in list_2: pass if a==b: list_3.append( a ) kvmap=defaultdict( int ) for k in list_3: kvmap[k]+=1 print kvmap Normally I use izip or izip_longest to club two for loops, but this time the length of the files are different. I don't want a None entry. If I use the above method, the run time becomes incremental and useless. How am I supposed to get the two for loops going? Cheers, Chavanak

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  • Technique to remove common words(and their plural versions) from a string

    - by Jake M
    I am attempting to find tags(keywords) for a recipe by parsing a long string of text. The text contains the recipe ingredients, directions and a short blurb. What do you think would be the most efficient way to remove common words from the tag list? By common words, I mean words like: 'the', 'at', 'there', 'their' etc. I have 2 methodologies I can use, which do you think is more efficient in terms of speed and do you know of a more efficient way I could do this? Methodology 1: - Determine the number of times each word occurs(using the library Collections) - Have a list of common words and remove all 'Common Words' from the Collection object by attempting to delete that key from the Collection object if it exists. - Therefore the speed will be determined by the length of the variable delims import collections from Counter delim = ['there','there\'s','theres','they','they\'re'] # the above will end up being a really long list! word_freq = Counter(recipe_str.lower().split()) for delim in set(delims): del word_freq[delim] return freq.most_common() Methodology 2: - For common words that can be plural, look at each word in the recipe string, and check if it partially contains the non-plural version of a common word. Eg; For the string "There's a test" check each word to see if it contains "there" and delete it if it does. delim = ['this','at','them'] # words that cant be plural partial_delim = ['there','they',] # words that could occur in many forms word_freq = Counter(recipe_str.lower().split()) for delim in set(delims): del word_freq[delim] # really slow for delim in set(partial_delims): for word in word_freq: if word.find(delim) != -1: del word_freq[delim] return freq.most_common()

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  • How to create instances of related models in Django

    - by sevennineteen
    I'm working on a CMSy app for which I've implemented a set of models which allow for creation of custom Template instances, made up of a number of Fields and tied to a specific Customer. The end-goal is that one or more templates with a set of custom fields can be defined through the Admin interface and associated to a customer, so that customer can then create content objects in the format prescribed by the template. I seem to have gotten this hooked up such that I can create any number of Template objects, but I'm struggling with how to create instances - actual content objects - in those templates. For example, I can define a template "Basic Page" for customer "Acme" which has the fields "Title" and "Body", but I haven't figured out how to create Basic Page instances where these fields can be filled in. Here are my (somewhat elided) models... class Customer(models.Model): ... class Field(models.Model): ... class Template(models.Model): label = models.CharField(max_length=255) clients = models.ManyToManyField(Customer, blank=True) fields = models.ManyToManyField(Field, blank=True) class ContentObject(models.Model): label = models.CharField(max_length=255) template = models.ForeignKey(Template) author = models.ForeignKey(User) customer = models.ForeignKey(Customer) mod_date = models.DateTimeField('Modified Date', editable=False) def __unicode__(self): return '%s (%s)' % (self.label, self.template) def save(self): self.mod_date = datetime.datetime.now() super(ContentObject, self).save() Thanks in advance for any advice!

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  • redefine __and__ operator

    - by wiso
    Why I can't redefine the __and__ operator? class Cut(object): def __init__(self, cut): self.cut = cut def __and__(self, other): return Cut("(" + self.cut + ") && (" + other.cut + ")") a = Cut("a>0") b = cut("b>0") c = a and b print c.cut() I want (a>0) && (b>0), but I got b, that the usual behaviour of and

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  • Scraping paginated items from a website using scrapy

    - by Mridang Agarwalla
    I'm using scrapy to scrape items from a site. I'm not being able to implement this scraping pattern. The site I'm trying to scrape is a forum and I scrape the site once a day. Each page has a table containing posts. New posts are added to the top of the table and as more and more posts are posted to the site, the older posts go further into the pages due to pagination. This is a very simple scenario and we will assume that the order of the posts never change. I would like to scrape this site and scrape all the "new" records until the last scraped post from yesterday is encountered. I have configured my spider to paginate endlessly and when it encounters yesterday's last scraped post, it should stop. How can implement this? (My Scrapy installation works with my Django installation using django-dynamic-scraper )

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  • Import boto from local library

    - by ensnare
    I'm trying to use boto as a downloaded library, rather than installing it globally on my machine. I'm able to import boto, but when I run boto.connect_dynamodb() I get an error: ImportError: No module named dynamodb.layer2 Here's my file structure: project/ project/ __init__.py libraries/ __init__.py flask/ boto/ views/ .... modules/ __init__.py db.py .... templates/ .... static/ .... runserver.py And the contents of the relevant files as follows: project/project/modules/db.py from project.libraries import boto conn = boto.connect_dynamodb( aws_access_key_id='<YOUR_AWS_KEY_ID>', aws_secret_access_key='<YOUR_AWS_SECRET_KEY>') What am I doing wrong? Thanks in advance.

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  • How do I join three tables with SQLalchemy and keeping all of the columns in one of the tables?

    - by jimka
    So, I have three tables: The class defenitions: engine = create_engine('sqlite://test.db', echo=False) SQLSession = sessionmaker(bind=engine) Base = declarative_base() class Channel(Base): __tablename__ = 'channel' id = Column(Integer, primary_key = True) title = Column(String) description = Column(String) link = Column(String) pubDate = Column(DateTime) class User(Base): __tablename__ = 'user' id = Column(Integer, primary_key = True) username = Column(String) password = Column(String) sessionId = Column(String) class Subscription(Base): __tablename__ = 'subscription' userId = Column(Integer, ForeignKey('user.id'), primary_key=True) channelId = Column(Integer, ForeignKey('channel.id'), primary_key=True) And the SQL commands that are executed to create them: CREATE TABLE subscription ( "userId" INTEGER NOT NULL, "channelId" INTEGER NOT NULL, PRIMARY KEY ("userId", "channelId"), FOREIGN KEY("userId") REFERENCES user (id), FOREIGN KEY("channelId") REFERENCES channel (id) ); CREATE TABLE user ( id INTEGER NOT NULL, username VARCHAR, password VARCHAR, "sessionId" VARCHAR, PRIMARY KEY (id) ); CREATE TABLE channel ( id INTEGER NOT NULL, title VARCHAR, description VARCHAR, link VARCHAR, "pubDate" TIMESTAMP, PRIMARY KEY (id) ); NOTE: I know user.username should be unique, need to fix that, and I'm not sure why SQLalchemy creates some row names with the double-quotes. And I'm trying to come up with a way to retrieve all of the channels, as well as an indication on what channels one particular user (identified by user.sessionId together with user.id) has a subscription on. For example, say we have four channels: channel1, channel2, channel3, channel4; a user: user1; who has a subscription on channel1 and channel4. The query for user1 would return something like: channel.id | channel.title | subscribed --------------------------------------- 1 channel1 True 2 channel2 False 3 channel3 False 4 channel4 True This is a best-case result, but since I have absolutely no clue as how to accomplish the subscribed column, I've been instead trying to get the particular users id in the rows where the user has a subscription and where a subscription is missing, just leave it blank. The database engine that I'm using together with SQLalchemy atm. is sqlite3 I've been scratching my head over this for two days now, I've no problem joining together all three by way of the subscription table but then all of the channels where the user does not have a subscription gets omitted. I hope I've managed to describe my problem sufficiently, thanks in advance.

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  • how to pass in dynamic data to decorators

    - by steve
    Hi, I am trying to write a base crud controller class that does the following: class BaseCrudController: model = "" field_validation = {} template_dir = "" @expose(self.template_dir) def new(self, *args, **kwargs) .... @validate(self.field_validation, error_handler=new) @expose() def post(self, *args, **kwargs): ... My intent is to have my controllers extend this base class, set the model, field_validation, and template locations, and am ready to go. Unfortunately, decorators (to my understanding), are interpreted when the function is defined. Hence it won't have access to instance's value. Is there a way to pass in dynamic data or values from the sub class? If not, I guess I could use override_template as a workaround to expose and set the template within the controller action. How would I go about validating the form within the controller action? Thanks, Steve

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  • How do I store multiple copies of the same field in Django?

    - by Alistair
    I'm storing OLAC metadata which describes linguistic resources. Many of the elements of the metadata are repeatable -- for example, a resource can have two languages, three authors and four dates associated with it. Is there any way of storing this in one model? It seems like overkill to define a model for each repeatable metadata element -- especially since the models will only have one field: it's value.

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  • ImportError and Django driving me crazy

    - by John Peebles
    OK, I have the following directory structure (it's a django project): - project -- app and within the app folder, there is a scraper.py file which needs to reference a class defined within models.py I'm trying to do the following: import urllib2 import os import sys import time import datetime import re import BeautifulSoup sys.path.append('/home/userspace/Development/') os.environ['DJANGO_SETTINGS_MODULE'] = 'project.settings' from project.app.models import ClassName and this code just isn't working. I get an error of: Traceback (most recent call last): File "scraper.py", line 14, in from project.app.models import ClassName ImportError: No module named project.app.models This code above used to work, but broke somewhere along the line and I'm extremely confused as to why I'm having problems. On SnowLeopard using python2.5.

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  • Create a color generator in matplotlib

    - by Brendan
    I have a series of lines that each need to be plotted with a separate colour. Each line is actually made up of several data sets (positive, negative regions etc.) and so I'd like to be able to create a generator that will feed one colour at a time across a spectrum, for example the gist_rainbow map shown here. I have found the following works but it seems very complicated and more importantly difficult to remember, from pylab import * NUM_COLORS = 22 mp = cm.datad['gist_rainbow'] get_color = matplotlib.colors.LinearSegmentedColormap.from_list(mp, colors=['r', 'b'], N=NUM_COLORS) ... # Then in a for loop this_color = get_color(float(i)/NUM_COLORS) Moreover, it does not cover the range of colours in the gist_rainbow map, I have to redefine a map. Maybe a generator is not the best way to do this, if so what is the accepted way?

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  • Dajano admin site foreign key fields

    - by user292652
    hi i have the following models setup class Player(models.Model): #slug = models.slugField(max_length=200) Player_Name = models.CharField(max_length=100) Nick = models.CharField(max_length=100, blank=True) Jersy_Number = models.IntegerField() Team_id = models.ForeignKey('Team') Postion_Choices = ( ('M', 'Manager'), ('P', 'Player'), ) Poistion = models.CharField(max_length=1, blank=True, choices =Postion_Choices) Red_card = models.IntegerField( blank=True, null=True) Yellow_card = models.IntegerField(blank=True, null=True) Points = models.IntegerField(blank=True, null=True) #Pic = models.ImageField(upload_to=path/for/upload, height_field=height, width_field=width, max_length=100) class PlayerAdmin(admin.ModelAdmin): list_display = ('Player_Name',) search_fields = ['Player_Name',] admin.site.register(Player, PlayerAdmin) class Team(models.Model): """Model docstring""" #slug = models.slugField(max_length=200) Team_Name = models.CharField(max_length=100,) College = models.CharField(max_length=100,) Win = models.IntegerField(blank=True, null=True) Loss = models.IntegerField(blank=True, null=True) Draw = models.IntegerField(blank=True, null=True) #logo = models.ImageField(upload_to=path/for/upload, height_field=height, width_field=width, max_length=100) class Meta: pass #def __unicode__(self): # return Team_Name #def save(self, force_insert=False, force_update=False): # pass @models.permalink def get_absolute_url(self): return ('view_or_url_name') class TeamAdmin(admin.ModelAdmin): list_display = ('Team_Name',) search_fields = ['Team_Name',] admin.site.register(Team, TeamAdmin) my question is how do i get to the admin site to show Team_name in the add player form Team_ID field currently it is only showing up as Team object in the combo box

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  • Pylons error handling

    - by TJ Huffington
    Hello, I am just getting started with Pylons and am confused as to how to account for exceptions. What is the proper way to error check user input (ensure a correct email address, check that it doesn't yet exist in the database, etc ...)? Should these checks go inside the model classes or somewhere else? Sample code would be great.

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  • Django: Determining if a user has voted or not

    - by TheLizardKing
    I have a long list of links that I spit out using the below code, total votes, submitted by, the usual stuff but I am not 100% on how to determine if the currently logged in user has voted on a link or not. I know how to do this from within my view but do I need to alter my below view code or can I make use of the way templates work to determine it? I have read http://stackoverflow.com/questions/1528583/django-vote-up-down-method but I don't quite understand what's going on ( and don't need any ofjavascriptery). Models (snippet): class Link(models.Model): category = models.ForeignKey(Category, blank=False, default=1) user = models.ForeignKey(User) created = models.DateTimeField(auto_now_add=True) modified = models.DateTimeField(auto_now=True) url = models.URLField(max_length=1024, unique=True, verify_exists=True) name = models.CharField(max_length=512) def __unicode__(self): return u'%s (%s)' % (self.name, self.url) class Vote(models.Model): link = models.ForeignKey(Link) user = models.ForeignKey(User) created = models.DateTimeField(auto_now_add=True) def __unicode__(self): return u'%s vote for %s' % (self.user, self.link) Views (snippet): links = Link.objects.select_related().annotate(votes=Count('vote')).order_by('-created')

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