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• Cache consistency & spawning a thread

  - by Dave Keck

  Background I've been reading through various books and articles to learn about processor caches, cache consistency, and memory barriers in the context of concurrent execution. So far though, I have been unable to determine whether a common coding practice of mine is safe in the strictest sense. Assumptions The following pseudo-code is executed on a two-processor machine: int sharedVar = 0; myThread() { print(sharedVar); } main() { sharedVar = 1; spawnThread(myThread); sleep(-1); } main() executes on processor 1 (P1), while myThread() executes on P2. Initially, sharedVar exists in the caches of both P1 and P2 with the initial value of 0 (due to some "warm-up code" that isn't shown above.) Question Strictly speaking – preferably without assuming any particular CPU – is myThread() guaranteed to print 1? With my newfound knowledge of processor caches, it seems entirely possible that at the time of the print() statement, P2 may not have received the invalidation request for sharedVar caused by P1's assignment in main(). Therefore, it seems possible that myThread() could print 0. References These are the related articles and books I've been reading. (It wouldn't allow me to format these as links because I'm a new user - sorry.) Shared Memory Consistency Models: A Tutorial hpl.hp.com/techreports/Compaq-DEC/WRL-95-7.pdf Memory Barriers: a Hardware View for Software Hackers rdrop.com/users/paulmck/scalability/paper/whymb.2009.04.05a.pdf Linux Kernel Memory Barriers kernel.org/doc/Documentation/memory-barriers.txt Computer Architecture: A Quantitative Approach amazon.com/Computer-Architecture-Quantitative-Approach-4th/dp/0123704901/ref=dp_ob_title_bk

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• asp.net mvc multiple fckeditors field

  - by mazhar kaunain baig

  how to add multiple fckeditor field on asp.net mvc page ok here is the code <% foreach (var OrganizationMeta in ((IEnumerable<Egovt.Models.OrganizationMeta>)ViewData["OrganizationMeta"])) { %> <% if (OrganizationMeta.vcr_DateType == "text") { %> <% TempData["OrganizationMeta"] = OrganizationMeta.vcr_MetaKey + Lang.int_LangId; %> <% Html.RenderPartial("ControlRender"); %> <% } %> <% } %> </div> controlrender <script src="<%= Url.Content("~/Content/js/fck/fckeditor.js") %>" type="text/javascript"></script> <script type="text/javascript"> window.onload = function() { var sBasePath = '<%= Url.Content("~/Content/js/fck/") %>'; var oFCKeditor = new FCKeditor('<%=TempData["OrganizationMeta"] %>'); oFCKeditor.BasePath = sBasePath; oFCKeditor.ReplaceTextarea(); } </script> <%= Html.TextArea(TempData["OrganizationMeta"].ToString(),"", new { @name = TempData["OrganizationMeta"] })%> How will i implement it

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• BlackBerry Library problems. (jre6 + NET_RIM_BLACKBERRY)

  - by kimera84

  Hi Everyone, I'm new in blackberry environement programming, I'm developing an application for this device and there are some probs about libraries that I don't understand. I have the main project called: npoBBerry - his library is NET_RIM_BLACKBERRY (from 4.6.1 version...) it includes other two projects: Npo - his library is standard jre6 (Npo inlcudes NpoCore) NpoCore - his library is standard jre6 Compliance was set... In Java Compiler level is set to 1.4 for all. Now the problem is that I'm not able to build my project. 4 errors: Error preverifying class ch.yek.npo.model.Advertising Error preverifying class ch.yek.npo.repository.Repository$1 Error!: Error: preverifier failed: C:\Program Files\eclipse\plugins\net.rim.eide.componentpack4.6.1_4.6.1.27\components\bin\preverify.ex ... Error!: Error: preverifier failed: C:\Program Files\eclipse\plugins\net.rim.eide.componentpack4.6.1_4.6.1.27\components\bin\preverify.ex ... I know that libraries are differents but maybe I'm missing something. NpoCore represents models, interfaces Npo just take data from a repository NpoBBeryy just use this data from Services... Please help and thanks in advance... :)

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• How to build a JSON response by combining @foo.to_json(options) and @bars.to_json(options) in Rails

  - by smotchkkiss

  First, the desired result I have User and Item models. I'd like to build a JSON response that looks like this: { "user": {"username":"Bob!","foo":"whatever","bar":"hello!"}, "items": [ {"id":1, "name":"one", "zim":"planet", "gir":"earth"}, {"id":2, "name":"two", "zim":"planet", "gir":"mars"} ] } However, my User and Item model have more attributes than just those. I found a way to get this to work, but beware, it's not pretty... Please help... My hacks home_controller.rb class HomeController < ApplicationController def observe respond_to do |format| format.js { render :json => Observation.new(current_user, @items).to_json } end end end observation.rb # NOTE: this is not a subclass of ActiveRecord::Base # this class just serves as a container to aggregate all "observable" objects class Observation attr_accessor :user, :items def initialize(user, items) self.user = user self.items = items end # The JSON needs to be decoded before it's sent to the `to_json` method in the home_controller otherwise the JSON will be escaped... # What a mess! def to_json { :user => ActiveSupport::JSON.decode(user.to_json(:only => :username, :methods => [:foo, :bar])), :items => ActiveSupport::JSON.decode(auctions.to_json(:only => [:id, :name], :methods => [:zim, :gir])) } end end

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• rails semi-complex STI with ancestry data model planning the routes and controllers

  - by ere

  I'm trying to figure out the best way to manage my controller(s) and models for a particular use case. I'm building a review system where a User may build a review of several distinct types with a Polymorphic Reviewable. Country (has_many reviews & cities) Subdivision/State (optional, sometimes it doesnt exist, also reviewable, has_many cities) City (has places & review) Burrow (optional, also reviewable ex: Brooklyn) Neighborhood (optional & reviewable, ex: williamsburg) Place (belongs to city) I'm also wondering about adding more complexity. I also want to include subdivisions occasionally... ie for the US, I might add Texas or for Germany, Baveria and have it be reviewable as well but not every country has regions and even those that do might never be reviewed. So it's not at all strict. I would like it to as simple and flexible as possible. It'd kinda be nice if the user could just land on one form and select either a city or a country, and then drill down using data from say Foursquare to find a particular place in a city and make a review. I'm really not sure which route I should take? For example, what happens if I have a Country, and a City... and then I decide to add a Burrow? Could I give places tags (ie Williamsburg, Brooklyn) belong_to NY City and the tags belong to NY? Tags are more flexible and optionally explain what areas they might be in, the tags belong to a city, but also have places and be reviewable? So I'm looking for suggestions for anyone who's done something related. Using Rails 3.2, and mongoid.

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• Hybrid EAV/CR model via WCF (and statically-typed language)?

  - by Pat

  Background I'm working on the architecture for a cloud-based LOB application, using Silverlight for the client, WCF, ASP.NET/C# for server and SQL Server for storage. The data model requires some flexibility per user (ability to add custom properties and define validation rules for them, for example), and a hybrid EAV/CR persistence model on the server side will suit nicely. Problem I need an efficient and maintainable technology and approach to handle the transformation from the persisted EAV model to/from WCF (and similarly allow the client to bind to the resulting data - DataGrid is a key UI element)? Admission: I don't yet know enough about WCF to understand if it supports ExpandoObject directly, but I suspect it will. Options I started off looking at WCF RIA services, but quickly discovered they're heavily dependent upon both static type data and compile-time code generation. Neither of these appeal. The options I'm considering include: Using WCF RIA services and pass the data over the network directly in EAV form (i.e. Dictionary), and handle the binding issue purely on the client side (like this) Using a dynamic language (probably IronPython) to handle both ends of the communication, with plumbing to generate the necessary CLR type data on the client to allow binding, and transform to/from EAV form on the server (spam preventer stopped me from posting a URL here, I'll try it in a comment). Dynamic LINQ (CreateClass() and friends), although I'm way out of my depth there and don't know what the limitations on that approach might be yet. I'm interested in comments on these approaches as well as alternative approaches that might solve the problem. Other Notes The Silverlight client will not be the only consumer of the service, making me slightly uncomfortable with option #1 above. While the data model is flexible, it's not expected to be modified heavily. For argument's sake, we could assume that we might have 25 distinct data models active at a given time, with something like 10-20 unique data fields/rules each. Modifications to the data model will happen infrequently (typically when a new user is initially configured).

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• PHP: Aggregate Model Classes or Uber Model Classes?

  - by sunwukung

  In many of the discussions regarding the M in MVC, (sidestepping ORM controversies for a moment), I commonly see Model classes described as object representations of table data (be that an Active Record, Table Gateway, Row Gateway or Domain Model/Mapper). Martin Fowler warns against the development of an anemic domain model, i.e. a class that is nothing more than a wrapper for CRUD functionality. I've been working on an MVC application for a couple of months now. The DBAL in the application I'm working on started out simple (on account of my understanding - oh the benefits of hindsight), and is organised so that Controllers invoke Business Logic classes, that in turn access the database via DAO/Transaction Scripts pertinent to the task at hand. There are a few "Entity" classes that aggregate these DAO objects to provide a convenient CRUD wrapper, but also embody some of the "behaviour" of that Domain concept (for example, a user - since it's easy to isolate). Taking a look at some of the code, and thinking along refactoring some of the code into a Rich Domain Model, it occurred to me that were I to try and wrap the CRUD routines and behaviour of say, a Company into a single "Model" class, that would be a sizeable class. So, my question is this: do Models represent domain objects, business logic, service layers, all of the above combined? How do you go about defining the responsibilities for these components?

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• Core Data @sum aggregate

  - by nasim

  I am getting an exception when I try to get @sum on a column in iPhone Core-Data application. My two models are following - Task model: @interface Task : NSManagedObject { } @property (nonatomic, retain) NSString * taskName; @property (nonatomic, retain) NSSet* completion; @end @interface Task (CoreDataGeneratedAccessors) - (void)addCompletionObject:(NSManagedObject *)value; - (void)removeCompletionObject:(NSManagedObject *)value; - (void)addCompletion:(NSSet *)value; - (void)removeCompletion:(NSSet *)value; @end Completion model: @interface Completion : NSManagedObject { } @property (nonatomic, retain) NSNumber * percentage; @property (nonatomic, retain) NSDate * time; @property (nonatomic, retain) Task * task; @end And here is the fetch: NSFetchRequest *request = [[NSFetchRequest alloc] init]; request.entity = [NSEntityDescription entityForName:@"Task" inManagedObjectContext:context]; NSSortDescriptor *sortDescriptor = [[NSSortDescriptor alloc] initWithKey:@"taskName" ascending:YES]; request.sortDescriptors = [NSArray arrayWithObject:sortDescriptor]; NSError *error; NSArray *results = [context executeFetchRequest:request error:&error]; NSArray *parents = [results valueForKeyPath:@"taskName"]; NSArray *children = [results valueForKeyPath:@"[email protected]"]; NSLog(@"%@ %@", parents, children); [request release]; [sortDescriptor release]; The exception is thrown at the fourth line from bottom. The thrown exception is: *** -[NSCFSet decimalValue]: unrecognized selector sent to instance 0x3b25a30 *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '*** -[NSCFSet decimalValue]: unrecognized selector sent to instance 0x3b25a30' I would very much appreciate any kind of help. Thanks.

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• How do I utilize REST to post GPS data from an Android device into a Ruby on Rails application?

  - by joecan

  I am a student in the process a building an Android app that can post a GPS track into a Rails application. I would like to do things the "Rails" way and take advantage of the REST. My rails application basically has 3 models at this point: users, tracks, and points. A user has_many tracks and a track has_many points. A track also has a total distance. Points have a latitude and longitude. I have successfully been able to create an empty track with: curl -i -X POST -H 'Content-Type: application/xml' -d '<track><distance>100</distance></track>' http://localhost:3000/users/1/tracks Whoo hoo! That is pretty cool. I am really impressed that rails do this. Just to see what would happen I tried the following: curl -i -X POST -H 'Content-Type: application/xml -d '<track><distance>100</distance><points><point><lat>3</lat><lng>2</lng></point></points></track>' http://localhost:3000/users/1/tracks Fail! The server spits back: Processing TracksController#create (for 127.0.0.1 at 2010-04-14 00:03:25) [POST] Parameters: {"track"={"points"={"point"={"lng"="2", "lat"="3"}}, "distance"="100"}, "user_id"="1"} User Load (0.6ms) SELECT * FROM "users" WHERE ("users"."id" = 1) ActiveRecord::AssociationTypeMismatch (Point(#-620976268) expected, got Array(#-607740138)): app/controllers/tracks_controller.rb:47:in `create' It seems my tracks_controller doesn't like or understand what it's getting from the params object in my tracks_controller.rb: def create @track = @user.tracks.build(params[:track]) My xml might be wrong, but at least Rails seems to be expecting a Point from it. Is there anyway I can fix TracksController.create so that it will be able to parse xml of a track with nested multiple points? Or is there another way I should be doing this entirely?

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• Bi-directional view model syncing with "live" collections and properties (MVVM)

  - by Schneider

  I am getting my knickers in a twist recently about View Models (VM). Just like this guy I have come to the conclusion that the collections I need to expose on my VM typically contain a different type to the collections exposed on my business objects. Hence there must be a bi-directional mapping or transformation between these two types. (Just to complicate things, on my project this data is "Live" such that as soon as you change a property it gets transmitted to other computers) I can just about cope with that concept, using a framework like Truss, although I suspect there will be a nasty surprise somewhere within. Not only must objects be transformed but a synchronization between these two collections is required. (Just to complicate things I can think of cases where the VM collection might be a subset or union of business object collections, not simply a 1:1 synchronization). I can see how to do a one-way "live" sync, using a replicating ObservableCollection or something like CLINQ. The problem then becomes: What is the best way to create/delete items? Bi-directinal sync does not seem to be on the cards - I have found no such examples, and the only class that supports anything remotely like that is the ListCollectionView. Would bi-directional sync even be a sensible way to add back into the business object collection? All the samples I have seen never seem to tackle anything this "complex". So my question is: How do you solve this? Is there some technique to update the model collections from the VM? What is the best general approach to this?

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• I have two choices of Master's classes this fall. Which is the most useful?

  - by ahplummer

  (For background purposes and context): I am a Software Engineer, and manage other Software Engineers currently. I kind of wear two hats right now: one of a programmer, and one as a 'team lead'. In this regard, I've started going back to school to get my Master's degree with an emphasis in Computer Science. I already have a Bachelor's in Computer Science, and have been working in the field for about 13 years. Our primary development environment is a Windows environment, writing in .NET, Delphi, and SQL Server. Choice #1: CST 798 DATA VISUALIZATION Course Description: Basically, this is a course on the "Processing" language: http://processing.org/ Choice #2: CST 711 INFORMATICS Course Description: (From catalog): Informatics is the science of the use and processing of data, information, and knowledge. This course covers a variety of applied issues from information technology, information management at a variety of levels, ranging from simple data entry, to the creation, design and implementation of new information systems, to the development of models. Topics include basic information representation, processing, searching, and organization, evaluation and analysis of information, Internet-based information access tools, ethics and economics of information sharing.

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• Creating self-referential tables with polymorphism in SQLALchemy

  - by Jace

  I'm trying to create a db structure in which I have many types of content entities, of which one, a Comment, can be attached to any other. Consider the following: from datetime import datetime from sqlalchemy import create_engine from sqlalchemy import Column, ForeignKey from sqlalchemy import Unicode, Integer, DateTime from sqlalchemy.orm import relation, backref from sqlalchemy.ext.declarative import declarative_base Base = declarative_base() class Entity(Base): __tablename__ = 'entities' id = Column(Integer, primary_key=True) created_at = Column(DateTime, default=datetime.utcnow, nullable=False) edited_at = Column(DateTime, default=datetime.utcnow, onupdate=datetime.utcnow, nullable=False) type = Column(Unicode(20), nullable=False) __mapper_args__ = {'polymorphic_on': type} # <...insert some models based on Entity...> class Comment(Entity): __tablename__ = 'comments' __mapper_args__ = {'polymorphic_identity': u'comment'} id = Column(None, ForeignKey('entities.id'), primary_key=True) _idref = relation(Entity, foreign_keys=id, primaryjoin=id == Entity.id) attached_to_id = Column(Integer, ForeignKey('entities.id'), nullable=False) #attached_to = relation(Entity, remote_side=[Entity.id]) attached_to = relation(Entity, foreign_keys=attached_to_id, primaryjoin=attached_to_id == Entity.id, backref=backref('comments', cascade="all, delete-orphan")) text = Column(Unicode(255), nullable=False) engine = create_engine('sqlite://', echo=True) Base.metadata.bind = engine Base.metadata.create_all(engine) This seems about right, except SQLAlchemy doesn't like having two foreign keys pointing to the same parent. It says ArgumentError: Can't determine join between 'entities' and 'comments'; tables have more than one foreign key constraint relationship between them. Please specify the 'onclause' of this join explicitly. How do I specify onclause?

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• Using Rails, problem testing has_many relationship

  - by east

  The summary is that I've code that works when manually testing, but isn't doing what I would think it should when trying to build an automated test. Here are the details: I've two models: Payment and PaymentTranscation. class Payment ... has_many :transactions, :class_name => 'PaymentTransaction' class PaymentTranscation ... belongs_to payment The PaymentTransaction is only created in a Payment model method, like so: def pay_up ... transactions.create!(params...) ... end I've manually tested this code, inspected the database, and everything works well. The failing automated test looks like this: def test_pay_up purchase = Payment.new(...) assert purchase.save assert_equal purchase.state, :initialized.to_s assert purchase.pay_up # this should create a new PaymentTransaction... assert_equal purchase.state, :succeeded.to_s assert_equal purchase.transactions.count, 1 # FAILS HERE; transactions is an empty array end If I step through the code, it's clear that the PaymentTransaction is getting created correctly (though I can't see it in the database because everything is in a testing transaction). What I can't figure out is why transactions is returning an empty array in the test when I know a valid PaymentTransaction is getting created. Anybody have some suggestions? Thanks in advance, east

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• Optimizing C# code in MVC controller

  - by cc0

  I am making a number of distinct controllers, one relating to each stored procedure in a database. These are only used to read data and making them available in JSON format for javascripts. My code so far looks like this, and I'm wondering if I have missed any opportunities to re-use code, maybe make some help classes. I have way too little experience doing OOP, so any help and suggestions here would be really appreciated. Here is my generalized code so far (tested and works); using System; using System.Configuration; using System.Web.Mvc; using System.Data; using System.Text; using System.Data.SqlClient; using Prototype.Models; namespace Prototype.Controllers { public class NameOfStoredProcedureController : Controller { char[] lastComma = { ',' }; String oldChar = "\""; String newChar = "&quot;"; StringBuilder json = new StringBuilder(); private String strCon = ConfigurationManager.ConnectionStrings["SomeConnectionString"].ConnectionString; private SqlConnection con; public StoredProcedureController() { con = new SqlConnection(strCon); } public string do_NameOfStoredProcedure(int parameter) { con.Open(); using (SqlCommand cmd = new SqlCommand("NameOfStoredProcedure", con)) { cmd.CommandType = CommandType.StoredProcedure; cmd.Parameters.AddWithValue("@parameter", parameter); using (SqlDataReader reader = cmd.ExecuteReader()) { while (reader.Read()) { json.AppendFormat("[{0},\"{1}\"],", reader["column1"], reader["column2"]); } } con.Close(); } if (json.Length.ToString().Equals("0")) { return "[]"; } else { return "[" + json.ToString().TrimEnd(lastComma) + "]"; } } //http://host.com/NameOfStoredProcedure?parameter=value public ActionResult Index(int parameter) { return new ContentResult { ContentType = "application/json", Content = do_NameOfStoredProcedure(parameter) }; } } }

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• Association and model data saving problem

  - by Zhlobopotam

  Developing with cakephp 1.3 (latest from github). There are 2 models bind with hasAndBelongsToMany: documents and tags. Document can have many tags in other words. I've add a new document submitting form there user can enter a list of tags separated with commas (new tag will be added, if not exist already). I looked at cakephp bakery 2.0 source code on github and found the solution. But it seems that something is wrong. class Document extends AppModel { public $hasAndBelongsToMany = array('Tag'); public function beforeSave($options = array()) { if (isset($this->data[$this->alias]['tags']) && !empty($this- >data[$this->alias]['tags'])) { $tagIds = $this->Tag->saveDocTags($this->data[$this->alias] ['tags']); unset($this->data[$this->alias]['tags']); $this->data[$this->Tag->alias][$this->Tag->alias] = $tagIds; } return true; } } class Tag extends AppModel { public $hasAndBelongsToMany = array ('Document'); public function saveDocTags($commalist = '') { if ($commalist == '') return null; $tags = explode(',',$commalist); if (empty($tags)) return null; $existing = $this->find('all', array( 'conditions' => array('title' => $tags) )); $return = Set::extract($existing,'/Tag/id'); if (sizeof($existing) == sizeof($tags)) { return $return; } $existing = Set::extract($existing,'/Tag/title'); foreach ($tags as $tag) { if (!in_array($tag, $existing)) { $this->create(array('title' => $tag)); $this->save(); $return[] = $this->id; } } return $return; } } So, new tags creation works well but document model can't save association data and tells: SQL Error: 1054: Unknown column 'Array' in 'field list' Query: INSERT INTO documents (title, content, shortnfo, date, status) VALUES ('Document with tags', '', '', Array, 1) Any ideas how to solve this problem?

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• Rails: Multi-Step New User Signup Form (FSM?)

  - by neezer

  I've read the "Create Multi-Step Wizard" in Advanced Rails Recipes. I've also read and re-read the documentation for the updated FSM I'm using called Workflow, and looked here and here. The Advanced Rails Recipe focuses on records (quizzes) that already exist, and doesn't cover creating new ones. The Workflow docs don't cover any code for controllers or views, so I've no idea what to do with all this model magic, and the last two links barely touch on implementation either. From the aforementioned resources, I have a good understanding of what a FSM in Rails is and how to play with it in the console or IRB, but I've got very little direction or understanding how to implement one into my Rails app. What I would like is this: a simple, multi-step user signup process. Step 1: User enters in their critical details (with validations). Step 2: User enters in their search criteria, for their profile (with validations). Step 3: User agrees to the Terms of Service (with validations). Step 4: User is greeted by a confirmation page, including a link that takes them to their newly created account. I'd also like full navigation between the steps and full capture (saves to the database) with each transition. Can someone please give me a clear implementation of something similar to this? I would LOVE an example app that includes a multi-step signup process where I can look at the code (FULL source code--models AND controllers and views) under the hood, but I've been unable to find anything like that. Any guidance would be appreciated! EDIT: Please help make this a Railscast! Ryan B. (a.k.a. Superman), if you're reading this, we need you! http://feedback.railscasts.com/forums/77-episode-suggestions/suggestions/35553-multi-step-forms-and-wizards

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• Save memory in Python. How to iterate over the lines and save them efficiently with a 2million line

  - by skyl

  I have a tab-separated data file with a little over 2 million lines and 19 columns. You can find it, in US.zip: http://download.geonames.org/export/dump/. I started to run the following but with for l in f.readlines(). I understand that just iterating over the file is supposed to be more efficient so I'm posting that below. Still, with this small optimization, I'm using 10% of my memory on the process and have only done about 3% of the records. It looks like, at this pace, it will run out of memory like it did before. Also, the function I have is very slow. Is there anything obvious I can do to speed it up? Would it help to del the objects with each pass of the for loop? def run(): from geonames.models import POI f = file('data/US.txt') for l in f: li = l.split('\t') try: p = POI() p.geonameid = li[0] p.name = li[1] p.asciiname = li[2] p.alternatenames = li[3] p.point = "POINT(%s %s)" % (li[5], li[4]) p.feature_class = li[6] p.feature_code = li[7] p.country_code = li[8] p.ccs2 = li[9] p.admin1_code = li[10] p.admin2_code = li[11] p.admin3_code = li[12] p.admin4_code = li[13] p.population = li[14] p.elevation = li[15] p.gtopo30 = li[16] p.timezone = li[17] p.modification_date = li[18] p.save() except IndexError: pass if __name__ == "__main__": run()

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• Can Core Data be used for objects with variable schemas?

  - by glenc

  I'm implementing a new iPhone app and am relatively new to Cocoa development overall. I am at the stage of choosing how the persistence layer of this app will work, and it looks like I'm basically choosing between Core Data and sqlite3. The persisted models in this app are intended to have a schema that is loaded at runtime (from some kind of defn file, probably XML). By which I mean, this app is intended to have objects that are user-definable to some extent, e.g. the Customer type (which has certain built-in fields like "name" and "email") can be modified to have extra fields based on the user's specific needs (e.g. a user might want to add a "favourite fruit" field to their Customer type). Having said that, will Core Data work for an app with a non-baked-in data model like this? I've just started playing around with the Core Data object designer thing in XCode and it seems like this thing wants to work with objects that have fixed fields that are compiled in. I'm definitely trying to take the path of least resistance here, and I can see the benefits of using an Apple-supplied data framework, but don't want to start down that path if it's going to lock me into a data model that's defined at compile time.

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• PHP: MVC and Model

  - by Pirkka

  Hello I`ve been wondering this one thing about creating models. If I make for example Page model. Is it the both: It can retrieve one row from the table or all the rows. Somehow Im mixing the objects and the database. I have thought it like this: I would have to make a Page-class that would represent one row in the table. It also would have all the basic CRUD-methods. Then I would have to do a Pages-class (somekind of collection) that would retrieve rows from the table and instantiate a Page object from each row. Is this kind of weird? If someone could explain to me the idea of model throughout.. Im again confused. Maybe Im thinking the whole OOP too difficult.. And by the way this forum is great. Hopefully people will just understand my problems. Heh. I was a long time procedural style programmer and now in 3 months I have dived into OOP and MVC and PHP frameworks and I just get more excited day by day when I explore this stuff!

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• Model binding & derived model classes

  - by Richard Ev

  Does ASP.NET MVC offer any simple way to get model binding to work when you have model classes that inherit from others? In my scenario I have a View that is strongly typed to List<Person>. I have a couple of classes that inherit from Person, namely PersonTypeOne and PersonTypeTwo. I have three strongly typed partial views with names that match these class names (and render form elements for the properties of their respective models). This means that in my main View I can have the following code: <% for(int i = 0; i < Model.Count; i++) { Html.RenderPartial(Model[i].GetType().Name, Model[i]); } %> This works well, apart from when the user submits the form the relevant controller action method just gets a List<Person>, rather than a list of Person, PersonTypeOne and PersonTypeTwo. This is pretty much as expected as the form submission doesn't contain enough information to tell the default model binder to create any instances of PersonTypeOne and PersonTypeTwo classes. So, is there any way to get such functionality from the default model binder?

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• How should backbone.js handle a GET request that returns no results?

  - by Nyxynyx

  I have a number of text input elements that when its values are changed, will trigger a fetch on listingListView's collection listingCollection, which then updates listingListView with the new data via the function listingListView.refreshList as shown below. I am using PHP/Codeigniter to expose a RESTful API. Problem: Everything works fine if there are results retrieved from the fetch(). However, when the filters results in no result being returned, how should the server side and the client side handle it? Currently Chrome's javascript console displays a 404 error and in the Network tab, the XHR request is highlighted in red. All I want to do in the event of zero results returned, is to blank the listingListView and show a message like (No results returned) and not throw any errors in the javascript console. Thanks! PHP Code function listings_get() { // Get filters $price_min = $this->get('price_min'); $this->load->model('app_model'); $results = $this->app_model->get_listings($price_min); if($results) $this->response($results); else $this->response(NULL); } JS Code window.ListingListView = Backbone.View.extend({ tagName: 'table', initialize: function() { this.model.bind('reset', this.refreshList, this); this.model.bind('add', function(listing) { $(this.el).append(new ListingListItemView({ model: listing }).render().el); }, this); }, render: function() { _.each(this.model.models, function(listing) { $(this.el).append(new ListingListItemView({ model: listing }).render().el); }, this); return this; }, close: function() { $(this.el).unbind(); $(this.el).empty(); }, refreshList: function() { $(this.el).empty(); this.render(); } });

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• How should I start to play with 3D

  - by MarceloRamires

  I'm a developer for just about 6 months now, and since I enjoy programming I make a couple of little programs. I've startedmaking encripters, calculators, tools, stuff to play with DropBox (hehe), stuff that play with bitmaps, drawing graphics, and even a program to update the MSN display image according to the artwork of the music you're listening yo on iTunes. Now I kind of ran off ideas of programs to deal with information, and I've had an idea: play around with 3d! so I've read a little about it and figured I'd have to have good notions on position and math on point spacial position (which I do, from my 3d modelling experience), but I don't know how to use API's for it, so I've 'simulated' simple 3d with a simple program I've made (it's just a spinning cube, please, first one to open it, comment here stating that it's safe, i've got no reason to harm anyone's pc.) One of my other hobbies is 3d modelling (completly amateur) and I'd like to mix these hobbies together! Here are some questions: 1) What would be a nice 3d development tool for a .NET programmer like me? 2) Is there a way of using 3d models made in 3DS Max ? (I intend on modelling characters) 3) What knowledges should I have in order to render it, and move it areound ? 4) Which API should I use ? NOTE: Not a dupe, I'm asking for directions specific for .NET development possibly using 3ds MAX, and there's no question about it!

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• Can I use a specific model from within a behavior in CakePHP?

  - by Paul Willy

  I'm trying to write a behavior that will give my models access to a simple workflow engine I've devised. The workflow engine itself works as a CakePHP model, with workflow data stored in the database just as any other model data is stored. Basically what I want to do is have the behavior use the workflow model whenever an action is called on the base model. For example, if the edit() action is executed for Posts, then the Post (with the behavior attached) will trigger the workflow behavior with its own model name, action, and id as arguments (e.g. [Post, edit, 1]). Then the behavior will invoke the functionality of the Workflow model, which has a record for what to do when edit is run on Posts (e.g. send e-mail to users who are subscribed to that post) and will carry that out. My question is, what is the proper way to invoke model/controller methods from within the behavior? The model to be used from within the behavior will always be Workflow, but the behavior should be usable from basically any model (aside from Workflow itself). I know I could run SQL queries directly from the behavior, but of course this is not the Cake way :-) Or, am I going about this in the wrong way? I want to store a certain amount of logic in the database so that it is easily configurable by different users, and not have endless configuration checks within the model/controller logic itself so that workflow steps can be easily added/changed/removed in the future.

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• how to parametrize an import in a View?

  - by Gianluca Colucci

  Hello everybody, I am looking for some help and I hope that some good soul out there will be able to give me a hint :) In the app I am building, I have a View. When an instance of this View gets created, it "imports" (MEF) the corresponding ViewModel. Here some code: public partial class ContractEditorView : Window { public ContractEditorView () { InitializeComponent(); CompositionInitializer.SatisfyImports(this); } [Import(ViewModelTypes.ContractEditorViewModel)] public object ViewModel { set { DataContext = value; } } } and here is the export for the ViewModel: [PartCreationPolicy(CreationPolicy.NonShared)] [Export(ViewModelTypes.ContractEditorViewModel)] public class ContractEditorViewModel: ViewModelBase { public ContractEditorViewModel() { _contract = new Models.Contract(); } } Now, this works if I want to open a new window to create a new contract... But it does not if I want to use the same window to edit an existing contract... In other words, I would like to add a second construct both in the View and in the ViewModel: the original constructor would accept no parameters and therefore it would create a new contract; the new construct - the one I'd like to add - I'd like to pass an ID so that I can load a given entity... What I don't understand is how to pass this ID to the ViewModel import... Thanks in advance, Cheers, Gianluca.

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• PHP: tips/resources/patterns for learning to implement a basic ORM

  - by BoltClock

  I've seen various MVC frameworks as well as standalone ORM frameworks for PHP, as well as other ORM questions here; however, most of the questions ask for existing frameworks to get started with, which is not what I'm looking for. (I have also read this SO question but I'm not sure what to make of it, and the answers are vague.) Instead, I figured I'd learn best by getting my hands dirty and actually writing my own ORM, even a simple one. Except I don't really know how to get started, especially since the code I see in other ORMs is so complicated. With my PHP 5.2.x (this is important) MVC framework I have a basic custom database abstraction layer, that has: Very simple methods like connect($host, $user, $pass, $base), query($sql, $binds), etc Subclasses for each DBMS that it supports A class (and respective subclasses) to represent SQL result sets But does not have: Active Record functionality, which I assume is an ORM thing (correct me if I'm wrong) I've read up a little about ORM, and from my understanding they provide a means to further abstract data models from the database itself by representing data as nothing more than PHP-based classes/objects; again, correct me if I am wrong or have missed out in any way. Still, I'd like some simple tips from anyone else who's dabbled more or less with ORM frameworks. Is there anything else I need to take note of, simple example code for me to refer to, or resources I can read? Thanks a lot in advance!

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