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  • OpenAL device, buffer and context relationship

    - by Markus
    I'm trying to create an object oriented model to wrap OpenAL and have a little problem understanding the devices, buffers and contexts. From what I can see in the Programmer's Guide, there are multiple devices, each of which can have multiple contexts as well as multiple buffers. Each context has a listener, and the alListener*() functions all operate on the listener of the active context. (Meaning that I have to make another context active first if I wanted to change it's listener, if I got that right.) So far, so good. What irritates me though is that I need to pass a device to the alcCreateContext() function, but none to alGenBuffers(). How does this work then? When I open multiple devices, on which device are the buffers created? Are the buffers shared between all devices? What happens to the buffers if I close all open devices? (Or is there something I missed?)

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  • Creating relationship between two model instances

    - by Lowgain
    This is probably pretty simple, but here: Say I've got two models, Thing and Tag class Thing < ActiveRecord::Base has_and_belongs_to_many :tags end class Tag < ActiveRecord::Base has_and_belongs_to_many :things end And I have an instance of each. I want to link them. Can I do something like: @thing = Thing.find(1) @tag = Tag.find(1) @thing.tags.add(@tag) If not, what is the best way to do this? Thanks!

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  • EF4: common interface for EF entities

    - by Feryt
    Hi. I have public interface: public interface IEntity { int ID { get; set; } string Name { get; set; } bool IsEnabled { get; set; } } ehich some EF entities implements(thanks to partial class) and extesion method: public static IEnumerable<SelectListItem> ToSelectListItems<T>(this IQueryable<T> entities, int? selectedID = null) where T : IEntity { return entities.Select(c => new { c.Name, c.ID }).ToList().Select(c => new SelectListItem { Text = c.Name, Value = c.ID.ToString(), Selected = (c.ID == selectedID) }); } Calling ToSelectListItems return exception: Unable to cast the type '<EF entity name>' to type 'IEntity'. LINQ to Entities only supports casting Entity Data Model primitive types. Why, any ideas? Thank you.

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  • ROR accepts_nested_attributes_for one to many relationship with selection

    - by bilash.saha
    I have two models Doctors and Questions like the follwong: Doctor Model class Doctor < ActiveRecord::Base has_many :questions has_many :brands accepts_nested_attributes_for :questions end Question model class Question < ActiveRecord::Base belongs_to :discipline belongs_to :doctor belongs_to :brand end Now you can clearly see that Doctor has many questions and brands and question belongs to doctor and brand.I want to add previously saved question to a doctor from doctors edit page. I want to remove them as well.How can I proceed ? I tried like : <%= form.fields_for :questions, question,:child_index => (question.new_record? ? "index_to_replace_with_js" : nil) do |question_form| %> <table> <tr> <td> <div class="label">Select Question</div> <%= question_form.collection_select :id, Question.all, :id, :title ,{:include_blank => true } %> </td> </tr> </table> but this doesnot works for me.Can you give me a solution with proper example ?

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  • Displaying a To-Many Relationship in a Table View

    - by DanF
    I've got an application I've been working on. There are projects and employees, projects can have several employees, employees can work on several projects. Right now I want selecting a project to display which employees are related to it, and allows me to add employees I select from another full-roster list. Somehow, this has proven more complicated, because (at least for now), selecting different projects still displays the same list of employees, as if all employees who'd been assigned to any project, belong to all of them. What part of Master-Detail am I missing?

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  • Validations for a has_many/belongs_to relationship

    - by Craig Walker
    I have a Recipe model which has_many Ingredients (which in turn belongs_to Recipe). I want Ingredient to be existent dependent on Recipe; an Ingredient should never exist without a Recipe. I'm trying to enforce the presence of a valid Recipe ID in the Ingredient. I've been doing this with a validates :recipe, :presence => true (Rails 3) statement in Ingredient. This works fine if I save the Recipe before adding an Ingredient to it's ingredients collection. However, if I don't have explicit control over the saving (such as when I'm creating a Recipe and its Ingredients from a nested form) then I get an error: Ingredients recipe can't be blank I can get around this simply by dropping the presence validation on Ingredient.recipe. However, I don't particularly like this, as it means I'm working without a safety net. What is the best way to enforce existence-dependence in Rails? Things I'm considering (please comment on the wisdom of each): Adding a not-null constraint on the ingredients.recipe_id database column, and letting the database do the checking for me. A custom validation that somehow checks whether the Ingredient is in an unsaved recipe's ingredient collection (and thus can't have a recipe_id but is still considered valid).

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  • Spring-Hibernate: How to submit a for when the object has one-to-many relations?

    - by Czar
    Hi, I have a form changeed the properties of my object CUSTOMER. Each customer has related ORDERS. The ORDER's table has a column customer_id which is used for the mapping. All works so far, I can read customers without any problem. When I now e.g. change the name of the CUSTOMER in the form (which does NOT show the orders), after saving the name is updated, but all relations in the ORDERS table are set to NULL (the customer_id for the items is set to NULL. How can I keep the relationship working? THX

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  • LINQ to Entity, joining on NOT IN tables

    - by SlackerCoder
    My brain seems to be mush right now! I am using LINQ to Entity, and I need to get some data from one table that does NOT exist in another table. For example: I need the groupID, groupname and groupnumber from TABLE A where they do not exist in TABLE B. The groupID will exist in TABLE B, along with other relevant information. The tables do not have any relationship. In SQL it would be quite simply (there is a more elegant and efficient solution, but I want to paint a picture of what I need) SELECT GroupID, GroupName, GroupNumber, FROM TableA WHERE GroupID NOT IN (SELECT GroupID FROM TableB) Is there an easy/elegant way to do this? Right now I have a bunch of queries hitting the db, then comparing, etc. It's pretty messy. Thanks.

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  • Possible relationship between PHP Mailer and Mailer-Daemon

    - by XGreen
    Hi, I am using the PHPMailer Class from a website which sends confirmation of the user ajax upload to my client. This uses the mail.myclient.com SMTP Host. This is the same SMTP Host that my client uses for his outlook to check his emails. This email from the website gets sent without errors although I have received two emails from my client regarding Mail delivery failed: returning message to sender for the same address I have used to send confirmation emails out from. Can these two issues be related? Do I need to provide more info? Thanks a bunch!

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  • TSQL, select values from large many-to-many relationship

    - by eugeneK
    I have two tables Publishers and Campaigns, both have similar many-to-many relationships with Countries,Regions,Languages and Categories. more info Publisher2Categories has publisherID and categoryID which are foreign keys to publisherID in Publishers and categoryID in Categories which are identity columns. On other side i have Campaigns2Categories with campaignID and categoryID columns which are foreign keys to campaignID in Campaigns and categoryID in Categories which again are identities. Same goes for Regions, Languages and Countries relationships I pass to query certain publisherID and want to get campaignIDs of Campaigns that have at least one equal to Publisher value from regions, countries, language or categories thanks

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  • Navigation properties not set when using ADO.NET Mocking Context Generator

    - by olenak
    I am using ADO.NET Mocking Context Generator plugin for my Entity Framework model. I have not started on using mocks yet, just trying to fix generated entity and context classes to make application run as before without exceptions. I've already fixed T4 template to support SaveChanges method. Now I've got another problem: when I try to access any navigation property it is set to null. All the primitive fields inherited from DB table are set and correct. So what I am doing is the following using (var context = MyContext()) { var order = context.Orders.Where(p => p.Id == 7); var product = order.Products; } in this case product is set to null. But that was not a case while using default code generator, it used to return real product object. Thanks ahead for any suggestions!

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  • how to model a many to many relationship

    - by Maulin
    Here is the scenario, Articles have many Comments Users can write many Comments for many Articles The comments table contains both user_id article_id as foreign keys My models are set up like so class User < ActiveRecord::Base has_many :comments has_many :articles, :through => :comments class Article < ActiveRecord::Base has_many :comments has_many :users, :through => :comments class Comment < ActiveRecord::Base belongs_to :users belongs_to :articles My routes.rb has the following code map.resources :articles, :has_many => :comments map.resources :users, :has_many => :comments which produces the following routes new_article_comment edit_article_comment new_user_comment edit_user_comment etc... This is not what I want (atleast not what I think I want), since comments must always be related to users and article, how can I get a route like so new_user_article_comment edit_user_article_comment Then I could just do new_user_article_comment_path([@user, @article]) to create a new comment

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  • many to many relationship mysql select

    - by zeina
    Let's consider 2 tables "schools" and "students". Now a student may belong to different schools in his life, and a school have many students. So this is a many to many example. A third table "links" specify the relation between student and school. Now to query this I do the following: Select sc.sid , -- stands for school id st.uid, -- stands for student id sc.sname, -- stands for school name st.uname, -- stands for student name -- select more data about the student joining other tables for that from students s left join links l on l.uid=st.uid -- l.uid stands for the student id on the links table left join schools sc on sc.sid=l.sid -- l.sid is the id of the school in the links table where st.uid=3 -- 3 is an example this query will return duplicate data for the user id if he has more than one school, so to fix this I added group by st.uid, yet I also need the list of school name related to the same user. Is there a way to do it with fixing the query I wrote instead of having 2 queries? So as example I want to have Luci of schools ( X, Y, Z, R, ...) etc

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  • Django Aggregation Across Reverse Relationship

    - by Tom
    Given these two models: class Profile(models.Model): user = models.ForeignKey(User, unique=True, verbose_name=_('user')) about = models.TextField(_('about'), blank=True) zip = models.CharField(max_length=10, verbose_name='zip code', blank=True) website = models.URLField(_('website'), blank=True, verify_exists=False) class ProfileView(models.Model): profile = models.ForeignKey(Profile) viewer = models.ForeignKey(User, blank=True, null=True) created = models.DateTimeField(auto_now_add=True) I want to get all profiles sorted by total views. I can get a list of profile ids sorted by total views with: ProfileView.objects.values('profile').annotate(Count('profile')).order_by('-profile__count') But that's just a dictionary of profile ids, which means I then have to loop over it and put together a list of profile objects. Which is a number of additional queries and still doesn't result in a QuerySet. At that point, I might as well drop to raw SQL. Before I do, is there a way to do this from the Profile model? ProfileViews are related via a ForeignKey field, but it's not as though the Profile model knows that, so I'm not sure how to tie the two together. As an aside, I realize I could just store views as a property on the Profile model and that may turn out to be what I do here, but I'm still interested in learning how to better use the Aggregation functions.

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  • Model Binding with Parent/Child Relationship

    - by user296297
    I'm sure this has been answered before, but I've spent the last three hours looking for an acceptable solution and have been unable to find anything, so I apologize for what I'm sure is a repeat. I have two domain objects, Player and Position. Player's have a Position. My domain objects are POCOs tied to my database with NHibernate. I have an Add action that takes a Player, so I'm using the built in model binding. On my view I have a drop down list that lets a user select the Position for the Player. The value of the drop down list is the Id of the position. Everything gets populated correctly except that my Position object fails validation (ModelState.IsValid) because at the point of model binding it only has an Id and none of it's other required attributes. What is the preferred solution for solving this with ASP.NET MVC 2? Solutions I've tried... Fetch the Position from the database based on the Id before ModelState.IsValid is called in the Add action of my controller. I can't get the model to run the validation again, so ModelState.IsValid always returns false. Create a custom ModelBinder that inherits from the default binder and fetch the Position from the database after the base binder is called. The ModelBinder seems to be doing the validation so if I use anything from the default binder I'm hosed. Which means I have to completely roll my own binder and grab every value from the form...this seems really wrong and inefficient for such a common use-case. Solutions I think might work, I just can't figure out how to do... Turn off the validation for the Position class when used in Player. Write a custom ModelBinder leverages the default binder for most of the property binding, but lets me get the Position from the database BEFORE the default binder runs validation. So, how do the rest of you solve this? Thanks, Dan P.S. In my opinion having a PositionId on Player just for this case is not a good solution. There has to be solvable in a more elegant fashion.

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  • django sort by manytomany relationship

    - by Marconi
    I have the following model: class Service(models.Model): ratings = models.ManyToManyField(User) Now if I wanna get all the service with ratings sorted in descending order I did something: services_list = Service.objects.filter(ratings__gt=0).distinct() services_list = list(services_list) services_list.sort(key=lambda service: service.ratings.all().count(), reverse=True) As you can see its a three step process and I don't feel right about this. Anybody who knows a better way to do this?

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  • Implementing Unowned relationship Google App Engine

    - by nwallman
    My question is more of a best practices question on how to implement unowned relationships with Google App Engine. I am using JDO to do my persistence and like recommended in the google docs I'm persisting my list of unowned relationships like so: @PersistenceCapable(identityType = IdentityType.APPLICATION) public class User implements Serializable, UserDetails { ... @Persistent private List<Key> groups; ... } Now I came across my predicament when I went to query that list of objects using they Key object. So when I get my list of group keys in order to actually return a list of Group objects I have to do a look up on that key to get the object. My question is what is the recommended way of doing a unowned look up on a model object? Should I have an instance of the PersistanceManagerFactory on my Model object so I can do a lookup? Should I have an instance of my GroupDAO object on my Model object so I can do a look up? Should I have a Utility to do this type of lookup? I'm new to this so I just want to know which is the best way to do this. Thanks.

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  • Access Relationship Table in Grails

    - by WaZ
    Hi, I have the following domains classes: class Posts{ String Name String Country static hasMany = [tags:Tags] static constraints = { } } class Tags{ String Name static belongsTo = Posts static hasMany = [posts:Posts] static constraints = { } String toString() { "${TypeName}" } } Grails creates an another table in the database i.e. Posts_Tags. My requirement is: E.g. 1 post has 3 tags. So, in the Posts_Tags table there are 3 rows. How can I access the table Posts_Tags directly in my code so that I can manipulate the data or add some more fields to it.

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  • Tables relationship in Cakephp

    - by kwokwai
    Hi all, I am new to Models structure in Cakephp. A few weeks ago I came across a tutorial in which the author got three tables in Database: Table A: {ID, Description, IsActive} Table B: {ID, TableA_ID, Description, CreationDate, ModifiedDate} Table A_B: {ID, TableA_ID, TableB_ID} The author of the tutorial said that the third table (Table A_B) is needed to run in CakePHP. I don't understand. Is there any specific documentation in CakePHP that I can refer to? I know there is a CookBook in Cakephp web site, but I couldn't find the relevant infromation.

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  • Best datastructure for this relationship...

    - by Travis
    I have a question about database 'style'. I need a method of storing user accounts. Some users "own" other user accounts (sub-accounts). However not all user accounts are owned, just some. Is it best to represent this using a table structure like so... TABLE accounts ( ID ownerID -> ID name ) ...even though there will be some NULL values in the ownerID column for accounts that do not have an owner. Or would it be stylistically preferable to have two tables, like so. TABLE accounts ( ID name ) TABLE ownedAccounts ( accountID -> accounts(ID) ownerID -> accounts(ID) ) Thanks for the advice.

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  • Do I need to manually create indexes for a DBIx::Class belongs_to relationship

    - by Dancrumb
    I'm using the DBIx::Class modules for an ORM approach to an application I have. I'm having some problems with my relationships. I have the following package MySchema::Result::ClusterIP; use strict; use warnings; use base qw/DBIx::Class::Core/; our $VERSION = '1.0'; __PACKAGE__->load_components(qw/InflateColumn::Object::Enum Core/); __PACKAGE__->table('cluster_ip'); __PACKAGE__->add_columns( # Columns here ); __PACKAGE__->set_primary_key('objkey'); __PACKAGE__->belongs_to( 'configuration' => 'MySchema::Result::Configuration', 'config_key'); __PACKAGE__->belongs_to( 'cluster' => 'MySchema::Result::Cluster', { 'foreign.config_key' => 'self.config_key', 'foreign.id' => 'self.cluster_id' } ); As well as package MySchema::Result::Cluster; use strict; use warnings; use base qw/DBIx::Class::Core/; our $VERSION = '1.0'; __PACKAGE__->load_components(qw/InflateColumn::Object::Enum Core/); __PACKAGE__->table('cluster'); __PACKAGE__->add_columns( # Columns here ); __PACKAGE__->set_primary_key('objkey'); __PACKAGE__->belongs_to( 'configuration' => 'MySchema::Result::Configuration', 'config_key'); __PACKAGE__->has_many('cluster_ip' => 'MySchema::Result::ClusterIP', { 'foreign.config_key' => 'self.config_key', 'foreign.cluster_id' => 'self.id' }); There are a couple of other modules, but I don't believe that they are relevant. When I attempt to deploy this schema, I get the following error: DBIx::Class::Schema::deploy(): DBI Exception: DBD::mysql::db do failed: Can't create table 'test.cluster_ip' (errno: 150) [ for Statement "CREATE TABLE `cluster_ip` ( `objkey` smallint(5) unsigned NOT NULL auto_increment, `config_key` smallint(5) unsigned NOT NULL, `cluster_id` char(16) NOT NULL, INDEX `cluster_ip_idx_config_key_cluster_id` (`config_key`, `cluster_id`), INDEX `cluster_ip_idx_config_key` (`config_key`), PRIMARY KEY (`objkey`), CONSTRAINT `cluster_ip_fk_config_key_cluster_id` FOREIGN KEY (`config_key`, `cluster_id`) REFERENCES `cluster` (`config_key`, `id`) ON DELETE CASCADE ON UPDATE CASCADE, CONSTRAINT `cluster_ip_fk_config_key` FOREIGN KEY (`config_key`) REFERENCES `configuration` (`config_key`) ON DELETE CASCADE ON UPDATE CASCADE ) ENGINE=InnoDB"] at test_deploy.pl line 18 (running "CREATE TABLE `cluster_ip` ( `objkey` smallint(5) unsigned NOT NULL auto_increment, `config_key` smallint(5) unsigned NOT NULL, `cluster_id` char(16) NOT NULL, INDEX `cluster_ip_idx_config_key_cluster_id` (`config_key`, `cluster_id`), INDEX `cluster_ip_idx_config_key` (`config_key`), PRIMARY KEY (`objkey`), CONSTRAINT `cluster_ip_fk_config_key_cluster_id` FOREIGN KEY (`config_key`, `cluster_id`) REFERENC ES `cluster` (`config_key`, `id`) ON DELETE CASCADE ON UPDATE CASCADE, CONSTRAINT `cluster_ip_fk_config_key` FOREIGN KEY (`config_key`) REFERENCES `configuration` (`conf ig_key`) ON DELETE CASCADE ON UPDATE CASCADE ) ENGINE=InnoDB") at test_deploy.pl line 18 From what I can tell, MySQL is complaining about the FOREIGN KEY constraint, in particular, the REFERENCE to (config_key, id) in the cluster table. From my reading of the MySQL documentation, this seems like a reasonable complaint, especially in regards to the third bullet point on this doc page. Here's my question. Am I missing something in the DBIx::Class module? I realize that I could explicitly create the necessary index to match up with this foreign key constraint, but that seems to be repetitive work. Is there something I should be doing to make this occur implicitly?

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  • JOIN in SQL with one-to-many relationship

    - by Kristopher Ives
    I'm making a tool to track calls to house/senate reps, and I have 2 tables of importance here: reps rep_id rep_name # and more info comments rep_id status # enum about result of contact comment I want to query for all reps joining the most recent associated comments and in some cases joining comments of a specific status, but there might not be any comments associated with that rep yet. THANKS!

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