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  • How do I keep a 3D model on the screen in OpenGL?

    - by NoobScratcher
    I'm trying to keep a 3D model on the screen by placing my glDrawElement functions inside the draw function with the declarations at the top of .cpp. When I render the model, the model attaches it self to the current vertex buffer object. This is because my whole graphical user interface is in 2D quads except the window frame. Is there a way to avoid this from happening? or any common causes of this? Creating the file object: int index = IndexAssigner(1, 1); //make a fileobject and store list and the index of that list in a c string ifstream file (list[index].c_str() ); //Make another string //string line; points.push_back(Point()); Point p; int face[4]; Model rendering code: int numfloats = 4; float* point=reinterpret_cast<float*>(&points[0]); int num_bytes=numfloats*sizeof(float); cout << "Size Of Point" << sizeof(Point) << endl; GLuint vertexbuffer; glGenVertexArrays(1, &vao[3]); glGenBuffers(1, &vertexbuffer); glBindBuffer(GL_ARRAY_BUFFER, vertexbuffer); glBufferData(GL_ARRAY_BUFFER, points.size()*sizeof(points), points.data(), GL_STATIC_DRAW); glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, num_bytes, &points[0]); glEnableClientState(GL_VERTEX_ARRAY); glVertexPointer(3, GL_FLOAT, points.size(), &points[0]); glEnableClientState(GL_INDEX_ARRAY); glIndexPointer(GL_FLOAT, faces.size(), faces.data()); glEnableVertexAttribArray(0); glDrawElements(GL_QUADS, points.size(), GL_UNSIGNED_INT, points.data()); glDrawElements(GL_QUADS, faces.size(), GL_UNSIGNED_INT, faces.data());

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  • How can I render a semi transparent model with OpenGL correctly?

    - by phobitor
    I'm using OpenGL ES 2 and I want to render a simple model with some level of transparency. I'm just starting out with shaders, and I wrote a simple diffuse shader for the model without any issues but I don't know how to add transparency to it. I tried to set my fragment shader's output (gl_FragColor) to a non opaque alpha value but the results weren't too great. It sort of works, but it looks like certain model triangles are only rendered based on the camera position... It's really hard to describe what's wrong so please watch this short video I recorded: http://www.youtube.com/watch?v=s0JqA0rZabE I thought this was a depth testing issue so I tried playing around with enabling/disabling depth testing and back face culling. Enabling back face culling changes the output slightly but the problem in the video is still there. Enabling/disabling depth testing doesn't seem to do anything. Could anyone explain what I'm seeing and how I can add some simple transparency to my model with the shader? I'm not looking for advanced order independent transparency implementations. edit: Vertex Shader: // color varying for fragment shader varying mediump vec3 LightIntensity; varying highp vec3 VertexInModelSpace; void main() { // vec4 LightPosition = vec4(0.0, 0.0, 0.0, 1.0); vec3 LightColor = vec3(1.0, 1.0, 1.0); vec3 DiffuseColor = vec3(1.0, 0.25, 0.0); // find the vector from the given vertex to the light source vec4 vertexInWorldSpace = gl_ModelViewMatrix * vec4(gl_Vertex); vec3 normalInWorldSpace = normalize(gl_NormalMatrix * gl_Normal); vec3 lightDirn = normalize(vec3(LightPosition-vertexInWorldSpace)); // save vertexInWorldSpace VertexInModelSpace = vec3(gl_Vertex); // calculate light intensity LightIntensity = LightColor * DiffuseColor * max(dot(lightDirn,normalInWorldSpace),0.0); // calculate projected vertex position gl_Position = gl_ModelViewProjectionMatrix * gl_Vertex; } Fragment Shader: // varying to define color varying vec3 LightIntensity; varying vec3 VertexInModelSpace; void main() { gl_FragColor = vec4(LightIntensity,0.5); }

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  • How accurate is "Business logic should be in a service, not in a model"?

    - by Jeroen Vannevel
    Situation Earlier this evening I gave an answer to a question on StackOverflow. The question: Editing of an existing object should be done in repository layer or in service? For example if I have a User that has debt. I want to change his debt. Should I do it in UserRepository or in service for example BuyingService by getting an object, editing it and saving it ? My answer: You should leave the responsibility of mutating an object to that same object and use the repository to retrieve this object. Example situation: class User { private int debt; // debt in cents private string name; // getters public void makePayment(int cents){ debt -= cents; } } class UserRepository { public User GetUserByName(string name){ // Get appropriate user from database } } A comment I received: Business logic should really be in a service. Not in a model. What does the internet say? So, this got me searching since I've never really (consciously) used a service layer. I started reading up on the Service Layer pattern and the Unit Of Work pattern but so far I can't say I'm convinced a service layer has to be used. Take for example this article by Martin Fowler on the anti-pattern of an Anemic Domain Model: There are objects, many named after the nouns in the domain space, and these objects are connected with the rich relationships and structure that true domain models have. The catch comes when you look at the behavior, and you realize that there is hardly any behavior on these objects, making them little more than bags of getters and setters. Indeed often these models come with design rules that say that you are not to put any domain logic in the the domain objects. Instead there are a set of service objects which capture all the domain logic. These services live on top of the domain model and use the domain model for data. (...) The logic that should be in a domain object is domain logic - validations, calculations, business rules - whatever you like to call it. To me, this seemed exactly what the situation was about: I advocated the manipulation of an object's data by introducing methods inside that class that do just that. However I realize that this should be a given either way, and it probably has more to do with how these methods are invoked (using a repository). I also had the feeling that in that article (see below), a Service Layer is more considered as a façade that delegates work to the underlying model, than an actual work-intensive layer. Application Layer [his name for Service Layer]: Defines the jobs the software is supposed to do and directs the expressive domain objects to work out problems. The tasks this layer is responsible for are meaningful to the business or necessary for interaction with the application layers of other systems. This layer is kept thin. It does not contain business rules or knowledge, but only coordinates tasks and delegates work to collaborations of domain objects in the next layer down. It does not have state reflecting the business situation, but it can have state that reflects the progress of a task for the user or the program. Which is reinforced here: Service interfaces. Services expose a service interface to which all inbound messages are sent. You can think of a service interface as a façade that exposes the business logic implemented in the application (typically, logic in the business layer) to potential consumers. And here: The service layer should be devoid of any application or business logic and should focus primarily on a few concerns. It should wrap Business Layer calls, translate your Domain in a common language that your clients can understand, and handle the communication medium between server and requesting client. This is a serious contrast to other resources that talk about the Service Layer: The service layer should consist of classes with methods that are units of work with actions that belong in the same transaction. Or the second answer to a question I've already linked: At some point, your application will want some business logic. Also, you might want to validate the input to make sure that there isn't something evil or nonperforming being requested. This logic belongs in your service layer. "Solution"? Following the guidelines in this answer, I came up with the following approach that uses a Service Layer: class UserController : Controller { private UserService _userService; public UserController(UserService userService){ _userService = userService; } public ActionResult MakeHimPay(string username, int amount) { _userService.MakeHimPay(username, amount); return RedirectToAction("ShowUserOverview"); } public ActionResult ShowUserOverview() { return View(); } } class UserService { private IUserRepository _userRepository; public UserService(IUserRepository userRepository) { _userRepository = userRepository; } public void MakeHimPay(username, amount) { _userRepository.GetUserByName(username).makePayment(amount); } } class UserRepository { public User GetUserByName(string name){ // Get appropriate user from database } } class User { private int debt; // debt in cents private string name; // getters public void makePayment(int cents){ debt -= cents; } } Conclusion All together not much has changed here: code from the controller has moved to the service layer (which is a good thing, so there is an upside to this approach). However this doesn't look like it had anything to do with my original answer. I realize design patterns are guidelines, not rules set in stone to be implemented whenever possible. Yet I have not found a definitive explanation of the service layer and how it should be regarded. Is it a means to simply extract logic from the controller and put it inside a service instead? Is it supposed to form a contract between the controller and the domain? Should there be a layer between the domain and the service layer? And, last but not least: following the original comment Business logic should really be in a service. Not in a model. Is this correct? How would I introduce my business logic in a service instead of the model?

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  • How do I map a composite primary key in Entity Framework 4 code first?

    - by jamesfm
    I'm getting to grips with EF4 code first, and liking it so far. But I'm having trouble mapping an entity to a table with a composite primary key. The configuration I've tried looks like this: public SubscriptionUserConfiguration() { Property(u => u.SubscriptionID).IsIdentity(); Property(u => u.UserName).IsIdentity(); } Which throws this exception: Unable to infer a key for entity type 'SubscriptionUser'. What am I missing?

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  • (Database Design - products attributes): What is better option for product attribute database design

    - by meyosef
    Hi, I new in database design. What is better option for product attribute database design for cms?(Please suggest other options also). option 1: 1 table products{ id product_name color price attribute_name1 attribute_value1 attribute_name2 attribute_value2 attribute_name3 attribute_value3 } option 2: 3 tables products{ id product_name color price } attribute{ id name value } products_attribute{ products_id attribute_id } Thanks, Yosef

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  • rspec & rails 3 cannot find model object

    - by Ceilingfish
    I'm trying to put some specs around a new rails 3 project I am working on, and my first test doesn't seem to be able to find a model. I've installed rspec from the command line using: sudo gem install rspec --pre and then I put the following in my Gemfile gem "rspec-rails", ">= 2.0.0.beta.1" But when I run my test I get ./spec/models/world_spec.rb:1: uninitialized constant World (NameError) rake aborted! Command /opt/local/bin/ruby -Ilib -Ispec "./spec/models/world_spec.rb" failed /opt/local/lib/ruby/gems/1.8/gems/rspec-core-2.0.0.beta.4/lib/rspec/core/rake_task.rb:71:in `define' /opt/local/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:1112:in `verbose' /opt/local/lib/ruby/gems/1.8/gems/rspec-core-2.0.0.beta.4/lib/rspec/core/rake_task.rb:57:in `send' /opt/local/lib/ruby/gems/1.8/gems/rspec-core-2.0.0.beta.4/lib/rspec/core/rake_task.rb:57:in `define' /opt/local/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:636:in `call' /opt/local/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:636:in `execute' /opt/local/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:631:in `each' /opt/local/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:631:in `execute' /opt/local/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:597:in `invoke_with_call_chain' /opt/local/lib/ruby/1.8/monitor.rb:242:in `synchronize' /opt/local/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:590:in `invoke_with_call_chain' /opt/local/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:583:in `invoke' /opt/local/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2051:in `invoke_task' /opt/local/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2029:in `top_level' /opt/local/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2029:in `each' /opt/local/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2029:in `top_level' /opt/local/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2068:in `standard_exception_handling' /opt/local/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2023:in `top_level' /opt/local/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2001:in `run' /opt/local/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:2068:in `standard_exception_handling' /opt/local/lib/ruby/gems/1.8/gems/rake-0.8.7/lib/rake.rb:1998:in `run' /opt/local/lib/ruby/gems/1.8/gems/rake-0.8.7/bin/rake:31 /opt/local/bin/rake:19:in `load' /opt/local/bin/rake:19 My spec is in spec/models/world_spec.rb, and looks like describe World, "#hello" do it "should be invalid" do World.new.should be_invalid? end end I tried adding a line like require "app/model/world" and require "world" but to no success. Does anyone know what I'm doing wrong?

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  • Database theory - relationship between two tables

    - by iansinke
    I have a database with two tables - let's call them Foo and Bar. Each foo may be related to any number of bars, and each bar may be related to any number of foos. I want to be able to retrieve, with one query, the foos that are associated with a certain bar, and the bars that are associated with a certain foo. My question is, what is the best way of recording these relationships? Should I have a separate table with records of each relationship (e.g. two columns, foo and bar)? Should the foo table have a column for a list of bars, and vice versa? Is there another option that I'm overlooking? I'm using SQL Server, if that makes a difference.

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  • UnboundLocalError: local variable 'rows' referenced before assignment

    - by patrick
    i'm trying to make a database connection by an other script. But the script didn't work propperly. and if I do a 'print' on the rows then I get the value 'null' But if I use a 'select * from incidents' query then i get the result from the table incidents. import database rows = database.database("INSERT INTO incidents VALUES(3 ,'test_title1', 'test', TO_DATE('25-07-2012', 'DD-MM-YYYY'), CURRENT_TIMESTAMP, 'sector', 50, 60)") #print database.database() print rows database.py script: import psycopg2 import sys import logfile def database(query): logfile.log(20, 'database.py', 'Executing...') con = None try: con = psycopg2.connect(database='incidents', user='ipfit5', password='tester') cur = con.cursor() #print query cur.execute(query) rows = cur.fetchall() con.commit() #test row does work #cur.execute("INSERT INTO incidents VALUES(3 ,'test_titel1', 'test', TO_DATE('25-07-2012', 'DD-MM-YYYY'), CURRENT_TIMESTAMP, 'sector', 50, 60)") except: logfile.log(40, 'database.py', 'Er is iets mis gegaan') logfile.log(40, 'database.py', str(sys.exc_info())) finally: if con: con.close() return rows

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  • Django and ImageField Question

    - by Hellnar
    Hello I have a such model: Foo (models.Model): slug = models.SlugField(unique=True) image = models.ImageField(upload_to='uploads/') I want to do two things with this: First of all, I want my image to be forced to resize to a specific width and height after the upload. I have tried this reading the documentation but seems to getting error: image = models.ImageField(upload_to='uploads/', height_field=258, width_field=425) Secondly, when adding an item via admin panel, I want my image's file name to be renamed as same as slug, if any issue arises (like if such named image already exists, add "_" to the end as it used to do. IE: My slug is i-love-you-guys , uploaded image such have i-love-you-guys.png at the end.

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  • Handling Model Inheritance in ASP.NET MVC2 & NHibernate

    - by enth
    I've gotten myself stuck on how to handle inheritance in my model when it comes to my controllers/views. Basic Model: public class Procedure : Entity { public Procedure() { } public int Id { get; set; } public DateTime ProcedureDate { get; set; } public ProcedureType Type { get; set; } } public ProcedureA : Procedure { public double VariableA { get; set; } public int VariableB { get; set; } public int Total { get; set; } } public ProcedureB : Procedure { public int Score { get; set; } } etc... many of different procedures eventually. So, I do things like list all the procedures: public class ProcedureController : Controller { public virtual ActionResult List() { IEnumerable<Procedure> procedures = _repository.GetAll(); return View(procedures); } } but now I'm kinda stuck. Basically, from the list page, I need to link to pages where the specific subclass details can be viewed/edited and I'm not sure what the best strategy is. I thought I could add an action on the ProcedureController that would conjure up the right subclass by dynamically figuring out what repository to use and loading the subclass to pass to the view. I had to store the class in the ProcedureType object. I had to create/implement a non-generic IRepository since I can't dynamically cast to a generic one. public virtual ActionResult Details(int procedureID) { Procedure procedure = _repository.GetById(procedureID, false); string className = procedure.Type.Class; Type type = Type.GetType(className, true); Type repositoryType = typeof (IRepository<>).MakeGenericType(type); var repository = (IRepository)DependencyRegistrar.Resolve(repositoryType); Entity procedure = repository.GetById(procedureID, false); return View(procedure); } I haven't even started sorting out how the view is going to determine which partial to load to display the subclass details. I'm wondering if this is a good approach? This makes determining the URL easy. It makes reusing the Procedure display code easy. Another approach is specific controllers for each subclass. It simplifies the controller code, but also means many simple controllers for the many procedure subclasses. Can work out the shared Procedure details with a partial view. How to get to construct the URL to get to the controller/action in the first place? Time to not think about it. Hopefully someone can show me the light. Thanks in advance.

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  • Opinions on sensor / reading / alert database design

    - by Mark
    I've asked a few questions lately regarding database design, probably too many ;-) However I beleive I'm slowly getting to the heart of the matter with my design and am slowly boiling it down. I'm still wrestling with a couple of decisions regarding how "alerts" are stored in the database. In this system, an alert is an entity that must be acknowledged, acted upon, etc. Initially I related readings to alerts like this (very cut down) : - [Location] LocationId [Sensor] SensorId LocationId UpperLimitValue LowerLimitValue [SensorReading] SensorReadingId Value Status Timestamp [SensorAlert] SensorAlertId [SensorAlertReading] SensorAlertId SensorReadingId The last table is associating readings with the alert, because it is the reading that dictate that the sensor is in alert or not. The problem with this design is that it allows readings from many sensors to be associated with a single alert - whereas each alert is for a single sensor only and should only have readings for that sensor associated with it (should I be bothered that the DB allows this though?). I thought to simplify things, why even bother with the SensorAlertReading table? Instead I could do this: [Location] LocationId [Sensor] SensorId LocationId [SensorReading] SensorReadingId SensorId Value Status Timestamp [SensorAlert] SensorAlertId SensorId Timestamp [SensorAlertEnd] SensorAlertId Timestamp Basically I'm not associating readings with the alert now - instead I just know that an alert was active between a start and end time for a particular sensor, and if I want to look up the readings for that alert I can do. Obviously the downside is I no longer have any constraint stopping me deleting readings that occurred during the alert, but I'm not sure that the constraint is neccessary. Now looking in from the outside as a developer / DBA, would that make you want to be sick or does it seem reasonable? Is there perhaps another way of doing this that I may be missing? Thanks. EDIT: Here's another idea - it works in a different way. It stores each sensor state change, going from normal to alert in a table, and then readings are simply associated with a particular state. This seems to solve all the problems - what d'ya think? (the only thing I'm not sure about is calling the table "SensorState", I can't help think there's a better name (maybe SensorReadingGroup?) : - [Location] LocationId [Sensor] SensorId LocationId [SensorState] SensorStateId SensorId Timestamp Status IsInAlert [SensorReading] SensorReadingId SensorStateId Value Timestamp There must be an elegant solution to this!

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  • OJB Reference Descriptor 1:0 relationship? Should I set auto-retrieve to false?

    - by godzillasdm
    Hi, I am having an issue while using Apache OJB with Spring 2 inside my web app. I'm using OJB reference-descriptor with 2 foreign key properties. I have an object A (parent) and object B (referenced object). The thing is, for an object A, there may or may not be an object B. In the case where there is no object B to go with Object A, the object B seems to be instantiated (through Spring?) anyways. However, I am unable to access object B's members. Whenever I test if Object B == null, it always returns false even though there is no matching value in the database. Since this Object is never null, I figured I can test the object's member like so: if( objectb.getDocumentNumber == null) { return false; } However, I get an exception in the jsp: javax.servlet.jsp.el.ELException: An error occurred while getting property "documentNumber" from an instance class org.sample.pojo.Objectb$$EnhancerByCGLIB$$78022a2 and this exception in the debugger when it's creating the objectB: com.sun.jdi.InvocationException occurred invoking method. I am guessing that the reference-descriptor must be a 1:1+ relationship, instead of a 1:0+ relationship. I was wondering if I should set the property 'auto-retrieve' to false, and then use the PersistenceBroker.retrieveAllReferences(Object obj); method as directed. However, this method's return value is 'void', so I am guessing that Spring somehow creates, and sets the reference class for me. (Returning me back to the same issue I'm having.) I will need a way to test whether the reference object exists first. If not, don't call this retrieveAllReferences method, but I don't see how. Am I going about this all wrong? Does reference-descriptor not allow 1:0 relations? Any work around to my problem? Your suggestions are greatly appreciated!

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  • Don't Understand Sql Server Error

    - by Jonathan Wood
    I have a table of users (User), and need to create a new table to track which users have referred other users. So, basically, I'm creating a many-to-many relation between rows in the same table. So I'm trying to create table UserReferrals with the columns UserId and UserReferredId. I made both columns a compound primary key. And both columns are foreign keys that link to User.UserID. Since deleting a user should also delete the relationship, I set both foreign keys to cascade deletes. When the user is deleted, any related rows in UserReferrals should also delete. But this gives me the message: 'User' table saved successfully 'UserReferrals' table Unable to create relationship 'FK_UserReferrals_User'. Introducing FOREIGN KEY constraint 'FK_UserReferrals_User' on table 'UserReferrals' may cause cycles or multiple cascade paths. Specify ON DELETE NO ACTION or ON UPDATE NO ACTION, or modify other FOREIGN KEY constraints. Could not create constraint. See previous errors. I don't get this error. A cascading delete only deletes the row with the foreign key, right? So how can it cause "cycling cascade paths"? Thanks for any tips.

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  • Best Role-Based Access Control (RBAC) database model

    - by jhs
    What is the best database schema to track role-based access controls for a web application? I am using Rails, but the RBAC plugin linked by Google looks unmaintained (only 300 commits to SVN; latest was almost a year ago). The concept is simple enough to implement from scratch, yet complex and important enough that it's worth getting right. So how do others architect and implement their RBAC model?

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  • django ManyToMany through help

    - by dotty
    Hay I've got a question about relationships. I want to Users to have Friendships. So a User can be a friend with another User. I'm assuming i'll need to use the ManyToManyField, through a Friendship table. But i cannot get it to work. Any ideas? Here are my models. class User(models.Model): username = models.CharField(max_length=999) password = models.CharField(max_length=999) created_on = models.DateField(auto_now = False, auto_now_add = True) updated_on = models.DateField(auto_now = True, auto_now_add = False) friends = models.ManyToManyField('User', through='Friendship') class Friendship(models.Model): user = models.ForeignKey('User') friend = models.ForeignKey('User') Thanks

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  • doctrine findby relation

    - by iggnition
    I'm having trouble selecting a subset of data with doctrine. I have 3 tables Location Contact Contact_location The contact and location tables hold a name and an id the other table holds only ID's. For instance: Location loc_id: 1 name: detroit Contact contact_id: 1 name: Mike Contact_location loc_id: 1 contact_id: 1 In doctrine there is a many to many relation between the location and contact tables with contact_location as the ref_class. What i want to do is on my location page i want to find all contacts where for instance the loc_id = 1. I tried: $this->installedbases = Doctrine::getTable('contact')->findByloc_id(1); hoping doctrine would see the relation and get it, but it does not. How can i make doctrine search in relevant related tables? I read it can be done using Findby but i find the documentation unclear.

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  • django error:The model Tribe is already registered

    - by zjm1126
    when i python manage.py syncdb,it show this: The following content types are stale and need to be deleted: maps | tribe Any objects related to these content types by a foreign key will also be deleted. Are you sure you want to delete these content types? If you're unsure, answer 'no'. Type 'yes' to continue, or 'no' to cancel: no when i put 'no' ,and then python manage runserver: AlreadyRegistered at / The model Tribe is already registered what should i do ? thanks

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  • Limiting choices from an intermediary ManyToMany junction table in Django

    - by Matthew Rankin
    Background I've created three Django models—Inventory, SalesOrder, and Invoice—to model items in inventory, sales orders for those items, and invoices for a particular sales order. Each sales order can have multiple items, so I've used an intermediary junction table—SalesOrderItems—using the through argument for the ManyToManyField. Also, partial billing of a sales orders is allowed, so I've created a ForeignKey in the Invoice model related to the SalesOrder model, so that a particular sales order can have multiple invoices. Here's where I deviate from what I've normally seen. Instead of relating the Invoice model to the Item model via a ManyToManyField, I've related the Invoice model to the SalesOrderItem intermediary junction table through the intermediary junction table InvoiceItem. I've done this because it better models reality—our invoices are tied to sales orders and can only include items that are tied to that sales order as opposed to any item in inventory. I will admit that it does seem strange having the intermediary junction table of a ManyToManyField related to the intermediary junction table of another ManyToManyField. Question How can I limit the choices available for the invoice_items in the Invoice model to just the sales_order_items of the SalesOrder model for that particular Invoice? (I tried using limit_choices_to= {'sales_order': self.invoice.sales_order}) as part of the item = models.ForeignKey(SalesOrderItem) in the InvoiceItem model, but that didn't work. Am I correct in thinking that limiting the choices for the invoice_items should be handled in the model instead of in a form? Code class Item(models.Model): item_num = models.SlugField(unique=True) default_price = models.DecimalField(max_digits=10, decimal_places=2, blank=True, null=True) class SalesOrderItem(models.Model): item = models.ForeignKey(Item) sales_order = models.ForeignKey('SalesOrder') unit_price = models.DecimalField(max_digits=10, decimal_places=2) quantity = models.DecimalField(max_digits=10, decimal_places=4) class SalesOrder(models.Model): customer = models.ForeignKey(Party) so_num = models.SlugField(max_length=40, unique=True) sales_order_items = models.ManyToManyField(Item, through=SalesOrderItem) class InvoiceItem(models.Model): item = models.ForeignKey(SalesOrderItem) invoice = models.ForeignKey('Invoice') unit_price = models.DecimalField(max_digits=10, decimal_places=2) quantity = models.DecimalField(max_digits=10, decimal_places=4) class Invoice(models.Model): invoice_num = models.SlugField(max_length=25) sales_order = models.ForeignKey(SalesOrder) invoice_items = models.ManyToManyField(SalesOrderItem, through='InvoiceItem')

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  • Examples of Hierarchical-Model-View-Controller (HMVC)?

    - by Stephen
    Hi, I'm interested in the Presentation-Abstraction-Control? (aka Hierarchical-Model-View-Controller (HMVC)) Architectural Pattern for constructing complex user interfaces (GUI or web) and was wondering if anyone was aware of any examples in the wild where I could read the code? My list so far; Cairngorm framework for Adobe Flex any others I'm aware of the JavaWorld article and associated letters cited in the wikipedia article http://en.wikipedia.org/wiki/Presentation-abstraction-control

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  • Database structure - To join or not to join

    - by Industrial
    Hi! We're drawing up the database structure with the help of mySQL Workbench for a new app and the number of joins required to make a listing of the data is increasing drastically as the many-to-many relationships increases. The application will be quite read-heavy and have a couple of hundred thousand rows per table. The questions: Is it really that bad to merge tables where needed and thereby reducing joins? Should we start looking at horizontal partitioning? (in conjunction with merging tables) Is there a better way then pivot tables to take care of many-to-many relationships? We discussed about instead storing all data in serialized text columns and having the application make the sorting instead of the database, but this seems like a very bad idea, even though that the database will be heavily cached. What do you think? Thanks!

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  • mysql Delete and Database Relationships

    - by Colin
    If I'm trying to delete multiple rows from a table and one of those rows can't be deleted because of a database relationship, what will happen? Will the rows that aren't constrained by a relationship still be deleted? Or will the entire delete fail? Thanks, Colin

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  • doctrine regenerating models from yml only the base models?

    - by TaMeR
    I am wondering if there is a way to handle this more elegantly. After generating the "main" models and base models from yml files the first time I have to add at the very leased an include for the base model to the "main" model like so: include_once 'generated/BaseBlog.php'; At the moment before I regenerate the models I move my changed main models, which is mostly way more then just the include path, in to a tmp folder then I delete all the models. And after regenerating I move my modified models back overwriting the generated main models. isn't there a way to just create the base models and not touch the main models? Or how do you guys handle this?

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