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  • Deleting entity with child relationships using .Net Entity Framework problem

    - by Am
    My God, EF is so frustrating. I can't seem to be able to get my head around what I need to do so I can delete an object. I seem to be able to remove the object but not the related child objects. Can anyone tell me what is the rule of thumb when you want to delete all related child objects of a given object? I've tried loading all related objects like this: if (!object.childobjects.IsLoaded) object.childobjects.Load(); but once I do the following I get errors related to the relationships: modelcontext.DeleteObject(object); modelcontext.SaveChanges(); Why can't I just load the object using modelcontext.GetObjectByKey and remove it along with its child objects? My other question is can I delete an object using Entity command like so? DELETE e from objectset as e where e.id = 12 I've tried few variations and all of them throw exceptions.

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  • Entity Framework 4.1 auto generate with DbContext when creating ADO.NET Entity Data Model

    - by smudgedlens
    I would like to work with DbContext instead of ObjectContext. I updated EF so now I have the DbContext, but I want to generate my strongly-typed context based on the DbContext and not the ObjectContext. When I add new ADO.NET Entity Data Model, it is still based on the ObjectContext. Is it not possible to have it base off of DbContext in Visual Studio 2010 with EF 4.1? UPDATE: Okay, I followed the directions in this link and was able to generate the DbContext template objects. However, now it is saying there is ambiguity between the template entities and the entities in my .edmx file. How do I resovle this? Do I blow away the ones in the .edmx file?

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  • Localized tables and Entity Framework

    - by Pyttroll
    Hi all, I have a scenario where I need to localized values of objects in my database. Let's say you have an application that can create animals, if the user is english the value of the "Name" property of an animal would be entered as "Cat" in the UI whereas it would be entered as "Chat" in french. The animal culture table would contain 2 records pointing to the same animal in the parent table. When reading values back, if the value of "Name" does not exist in the user culture the default value (value the object was originally created with) would be used. The following diagrams demonstrate how the data is stored in SQL: I'm trying to map this schema to an object model using the Entity Framework, I'm a bit confused as to what the best way to approach the problem. Is EF appropriate for this? Should I used EF4? This EF model will be used by .NET RIA Services. Thanks, Pierre-Yves Troel Ayuda Media Systems http://www.ayudasystems.com

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  • Role of an entity state in a component based system?

    - by Paul
    Component-based entity systems are all the rage these days; everyone seems to agree they are the way to go, but no one really has a definitive implementation of such a system. I was wondering, what role do entity states (walking-left, standing, jumping, etc) have in a CBS? Do they act like controllers (i.e. they handle events and change the entity's attributes based on those events)? What about cases where a state would, for example, require that the entity enters no-clip mode? Should, that state, when it enters, maybe set the CollisionComponent of the entity to a null pointer or something? (Then, on exit, the state should restore the entity's CollisionComponent to its previous state.) Also, I guess it's the current state's job to change the entity's state to something else, right?

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  • Entity Framework - Foreign key constraints not added for inherited entity

    - by Tri Q
    Hello, It appears to me that a strange phenomenon is occurring with inherited entities (TPT) in EF4. I have three entities. 1. Asset 2. Property 3. Activity Property is a derived-type of Asset. Property has many activities (many-to-many) When modeling this in my EDMX, everything seems fine until I try to insert a new Property into the database. If the property does not contain any Activity, it works, but all hell breaks loose when I add some new activities to the new Property. As it turns out after 2 days of crawling the web and fiddling around, I noticed that in the EF store (SSDL) some of the constraints between entities were not picked up during the update process. Property_Activity table which links properties and activities show only one constraint FK_Property_Activity_Activity but FK_Property_Activity_Property was missing. I knew this is an Entity Framework anomoly because when I switched the relationship in the database to: Asset <-- Asset_Activity <-- Activity After an update, all foreign key constraints are picked up and the save is successful, with or without activities in the new property. Is this intended or a bug in EF? How do I get around this problem? Should I abandon inheritance altogether?

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  • How to remove a model object from an EMF model and its GEF Editor via Adapter

    - by s.d
    This question is principally a follow-up to my question about EMF listening mechanisms. So, I have a third-party EMF model (uneditable) which is based on a generic graph model. The structure is as follows: Project | ItemGraph | Item | Document | DocumentGraph / | \ Tokens Nodes Relations(Edges) I have a GEF editor which works on the DocumentGraph (i.e., not the root object, perhaps this is a problem?): getGraphicalViewer().setContents(documentGraph). THe editor has the following edit part structure: DocumentGraphEP / \ Primary Connection LayerEP LayerEP / \ | TokenEP NodeEP RelationEP PrimaryLayerEP and ConnectionLayerEP both have simple Strings as model, which are not represented in the EMF (domain) model. They are simply used to add a primary (i.e., node) layer, and a connection layer (with ShortestPathConnectionRouter) to the editor. Problem: I am trying to get myself into the workings of EMF adapters, and have tried to make use of the available tutorials, mainly the EMF-GEF Eclipse tutorial, vainolo's blog, and vogella's tutorial. I thought I'd start with an easy thing, so tried to remove a node from the graph and see if I get it to work. Which I didn't, and I don't see where the problem is. I can select a node, and have the generic delete Action in my toolbar, but when I click it, nothing happens. Here is the respective source code for the different responsible parts. Please be so kind to point me to any errors (of thinking, coding errors, whathaveyou) you can find. NodeEditPart public class NodeEditPart extends AbstractGraphicalEditPart implements Adapter { protected IFigure createFigure() { return new NodeFigure(); } protected void createEditPolicies() { .... installEditPolicy(EditPolicy.COMPONENT_ROLE, new NodeComponentEditPolicy()); } protected void refreshVisuals() { NodeFigure figure = (NodeFigure) getFigure(); SNode model = (SNode) getModel(); PrimaryLayerEditPart parent = (PrimaryLayerEditPart) getParent(); // Set text figure.getLabel().setText(model.getSName()); .... } public void activate() { if (isActive()) return; // start listening for changes in the model ((Notifier)getModel()).eAdapters().add(this); super.activate(); } public void deactivate() { if (!isActive()) return; // stop listening for changes in the model ((Notifier)getModel()).eAdapters().remove(this); super.deactivate(); } private Notifier getSDocumentGraph() { return ((SNode)getModel()).getSDocumentGraph(); } @Override public void notifyChanged(Notification notification) { int type = notification.getEventType(); switch( type ) { case Notification.ADD: case Notification.ADD_MANY: case Notification.REMOVE: case Notification.REMOVE_MANY: refreshChildren(); break; case Notification.SET: refreshVisuals(); break; } } @Override public Notifier getTarget() { return target; } @Override public void setTarget(Notifier newTarget) { this.target = newTarget; } @Override public boolean isAdapterForType(Object type) { return type.equals(getModel().getClass()); } } NodeComponentEditPolicy public class NodeComponentEditPolicy extends ComponentEditPolicy { public NodeComponentEditPolicy() { super(); } protected Command createDeleteCommand(GroupRequest deleteRequest) { DeleteNodeCommand cmd = new DeleteNodeCommand(); cmd.setSNode((SNode) getHost().getModel()); return cmd; } } DeleteNodeCommand public class DeleteNodeCommand extends Command { private SNode node; private SDocumentGraph graph; @Override public void execute() { node.setSDocumentGraph(null); } @Override public void undo() { node.setSDocumentGraph(graph); } public void setSNode(SNode node) { this.node = node; this.graph = node.getSDocumentGraph(); } } All seems to work fine: When a node is selected in the editor, the delete symbol is activated in the toolbar, but when it is clicked, nothing happens in the editor. I'd be very thankful for any pointers :).

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  • Entity Framework and differences between Contains between SQL and objects using ToLower

    - by John Ptacek
    I have run into an "issue" I am not quite sure I understand with Entity Framework. I am using Entity Framework 4 and have tried to utilize a TDD approach. As a result, I recently implemented a search feature using a Repository pattern. For my test project, I am implementing my repository interface and have a set of "fake" object data I am using for test purposes. I ran into an issue trying to get the Contains clause to work for case invariant search. My code snippet for both my test and the repository class used against the database is as follows: if (!string.IsNullOrEmpty(Description)) { items = items.Where(r => r.Description.ToLower().Contains(Description.ToLower())); } However, when I ran my test cases the results where not populated if my case did not match the underlying data. I tried looking into what I thought was an issue for a while. To clear my mind, I went for a run and wondered if the same code with EF would work against a SQL back end database, since SQL will explicitly support the like command and it executed as I expected, using the same logic. I understand why EF against the database back end supports the Contains clause. However, I was surprised that my unit tests did not. Any ideas why other than the SQL server support of the like clause when I use objects I populate in a collection instead of against the database server? Thanks! John

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  • Seeding many to many tables with Entity Framework

    - by Doozer1979
    I have a meeting entity and a users entity which have a many to many relationship. I'm using Autopoco to create seed data for the Users and meetings How do i seed the UserMeetings linking table that is created by EntityFramework with seed data? The linking table has two fields in it; User_Id, and Meeting_ID. I'm looping through the list of users that autopoco creates and attaching a random number of meetings Here's what i've got so far. foreach (var user in userList) { var rand = new Random(); var amountOfMeetingsToAdd = rand.Next(1, 300); for (var i = 0; i <= amountOfMeetingsToAdd; i++) { var randomMeeting = rand.Next(1, MeetingRecords); //Error occurs on This line user.Meetings.Add(_meetings[randomMeeting]); } } I got an 'Object reference not set to an instance of an object.' even though the meeting record that i'm trying to attach does exist. For info all this is happening prior to me saving the context to the DB.

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  • Entity Framework one-to-one relationship mapping flattened in code

    - by Josh Close
    I have a table structure like so. Address: AddressId int not null primary key identity ...more columns AddressContinental: AddressId int not null primary key identity foreign key to pk of Address County State AddressInternational: AddressId int not null primary key identity foreign key to pk of Address ProvinceRegion I don't have control over schema, this is just the way it is. Now, what I want to do is have a single Address object. public class Address { public int AddressId { get; set; } public County County { get; set; } public State State { get; set } public ProvinceRegion { get; set; } } I want to have EF pull it out of the database as a single entity. When saving, I want to save the single entity and have EF know to split it into the three tables. How would I map this in EF 4.1 Code First? I've been searching around and haven't found anything that meets my case yet. UPDATE An address record will have a record in Address and one in either AddressContinental or AddressInternational, but not both.

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  • Entity Framework - Insert/Update new entity with child-entities

    - by Christina Mayers
    I have found many questions here on SO and articles all over the internet but none really tackled my problem. My model looks like this (I striped all non essential Properties): Everyday or so "Play" gets updated (via a XML-file containing the information). internal Play ParsePlayInfo(XDocument doc) { Play play = (from p in doc.Descendants("Play") select new Play { Theatre = new Theatre() { //Properties }, //Properties LastUpdate = DateTime.Now }).SingleOrDefault(); var actors = (from a in doc.XPathSelectElement(".//Play//Actors").Nodes() select new Lecturer() { //Properties }); var parts = (from p in doc.XPathSelectElement(".//Play//Parts").Nodes() select new Part() { //Properties }).ToList(); foreach (var item in parts) { play.Parts.Add(item); } var reviews = (from r in doc.XPathSelectElement(".//Play//Reviews").Nodes() select new Review { //Properties }).ToList(); for (int i = 0; i < reviews.Count(); i++) { PlayReviews pR = new PlayReviews() { Review = reviews[i], Play = play, //Properties }; play.PlayReviews.Add(pR); } return play; } If I add this "play" via Add() every Childobject of Play will be inserted - regardless if some exist already. Since I need to update existing entries I have to do something about that. As far as I can tell I have the following options: add/update the child entities in my PlayRepositories Add-Method restructure and rewrite ParsePlayInfo() so that get all the child entities first, add or update them and then create a new Play. The only problem I have here is that I wanted ParsePlayInfo() to be persistence ignorant, I could work around this by creating multiple parse methods (eg ParseActors() ) and assign them to play in my controller (I'm using ASP.net MVC) after everything was parsed and added Currently I am implementing option 1 - but it feels wrong. I'd appreciate it if someone could guide me in the right direction on this one.

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  • Camera wont stay behind model after pitch, then rotation

    - by ChocoMan
    I have a camera position behind a model. Currently, if I push the left thumbstick making my model move forward, backward, or strafe, the camera stays with the model. If I push the right thumbstick left or right, the model rotates in those directions fine along with the camera rotating while maintaining its position relatively behind the model. But when I pitch the model up or down, then rotate the model afterwards, the camera moves slightly rotates in a clock-like fashion behind the model. If I do a few rotations of the model and try to pitch the camera, the camera will eventually be looking at the side, then eventually the front of the model while also rotating in a clock-like fashion. My question is, how do I keep the camera to pitch up and down behind the model no matter how much the model has rotated? Here is what I got: // Rotates model and pitches camera on its own axis public void modelRotMovement(GamePadState pController) { // Rotates Camera with model Yaw = pController.ThumbSticks.Right.X * MathHelper.ToRadians(angularSpeed); // Pitches Camera around model Pitch = pController.ThumbSticks.Right.Y * MathHelper.ToRadians(angularSpeed); AddRotation = Quaternion.CreateFromYawPitchRoll(Yaw, 0, 0); ModelLoad.MRotation *= AddRotation; MOrientation = Matrix.CreateFromQuaternion(ModelLoad.MRotation); } // Orbit (yaw) Camera around with model (only seeing back of model) public void cameraYaw(Vector3 axisYaw, float yaw) { ModelLoad.CameraPos = Vector3.Transform(ModelLoad.CameraPos - ModelLoad.camTarget, Matrix.CreateFromAxisAngle(axisYaw, yaw)) + ModelLoad.camTarget; } // Raise camera above or below model's shoulders public void cameraPitch(Vector3 axisPitch, float pitch) { ModelLoad.CameraPos = Vector3.Transform(ModelLoad.CameraPos - ModelLoad.camTarget, Matrix.CreateFromAxisAngle(axisPitch, pitch)) + ModelLoad.camTarget; } // Call in update method public void updateCamera() { cameraYaw(Vector3.Up, Yaw); cameraPitch(Vector3.Right, Pitch); } NOTE: I tried to use addPitch just like addRotation but it didn't work...

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  • Entity Framework 4 "Generate Database from Model" to SQLEXPRESS mdf results in "Could not locate ent

    - by InfinitiesLoop
    I'm using Visual Studio 2010 RTM. I want to do model-first, so I started a new MVC app and added a new blank edmx. Created a few entities. No problem. Then I "Generate Database from Model", and allow the dialog to create a new database for me, which it does successfully as 'mydatabase.mdf' in the app's App_Data directory. Then I open the generated sql file (in Visual Studio). To run it of course I have to give it a connection. I am not sure if it's right, but I used '.\SQLEXPRESS' and Windows authentication. No idea how I'd tell it where the MDF is. Then the problem -- upon executing it, I get: Msg 911, Level 16, State 1, Line 1 Could not locate entry in sysdatabases for database 'mydatabase'. No entry found with that name. Make sure that the name is entered correctly. And indeed there were no tables created in the MDF. So... what am I doing wrong, or am I off my rocker expecting this to work? :)

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  • Entity Framework naming conventions for many-to-many link tables

    - by TimothyP
    Hi, We are designing a SQL Server database with link tables for many-to-many relations. The question is are there any best practices for naming these kinds of tables for use with the entity framework? Let's say there's a table Customer and Address Then there is a link table between them, what do we call it? CustomerAddress ? Or something else? Thnx

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  • SQL Server backward compatibility in Entity Framework?

    - by shake
    Is there any backward compatibility in the entity framework between SQL Server 2008 and 2005? It seems the framework forces you to use the same provider for all the .edmx files in a solution. If you use the 2008 provider, data types like DateTime2 and functions like SysDateTime that are emitted by the framework to the underlying SQL query make it useless to use them against a SQL 2005 Server. Any way around this?

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  • How to create entities in one Entity group ?

    - by Gopi
    I am building an app based on google app engine (Java) using JDO for persistence. Can someone give me an example or a point me to some code which shows persisting of multiple entities (of same type) using javax.jdo.PersistenceManager.makePersistentAll() within a transaction. Basically I need to understand how to put multiple entites in one Entity Group so that they can be saved using makePersistentAll() inside transaction.

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  • Entity Framework Code-First to Provide Replacement for ASP.NET Profile Provider

    - by Ken Cox [MVP]
    A while back, I coordinated a project to add support for the SQL Table Profile Provider in ASP.NET 4 Web Applications.  We urged Microsoft to improve ASP.NET’s built-in Profile support so our workaround wouldn’t be necessary. Instead, Microsoft plans to provide a replacement for ASP.NET Profile in a forthcoming release. In response to my feature suggestion on Connect, Microsoft says we should look for something even better using Entity Framework: “When code-first is officially released the final piece of a full replacement of the ASP.NET Profile will have arrived. Once code-first for EF4 is released, developers will have a really easy and very approachable way to create any arbitrary class, and automatically have the .NET Framework create a table to provide storage for that class. Furthermore developer will also have full LINQ-query capabilities against code-first classes. “ The downside is that there won’t be a way to retrofit this Profile replacement to pre- ASP.NET 4 Web applications. At least there’ll still be the MVP workaround code. It looks like it’s time for me to dig into a CTP of EF Code-First to see what’s available.   Scott Guthrie has been blogging about Code-First Development with Entity Framework 4. It’s not clear when the EF Code-First is coming, but my guess is that it’ll be part of the VS 2010/.NET 4 service pack.

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  • Texture switching with a entity system

    - by GameDev-er
    I'm using thinking of using an entity system in my game. So far I've been using Artemis with success. However, I have a question about texture switching. I read that switching textures too often is bad. So I load all the textures when the game loads like so: import org.newdawn.slick.opengl.TextureLoader; ... public HashMap<String, Texture> Textures; ... Then for each texture I do this: Texture tex = TextureLoader.getTexture("PNG", this.getClass().getResourceAsStream(texturePath)); Textures.put(textureName, tex); Then when drawing entities I do this: drawEntity() { glBindTexture(GL_TEXTURE_2D, Textures.get(entityTexture).getTextureID()); ... } Say I have 50 entities, using 10 different 3D models, each with their own texture. When the drawEntity system runs, it doesn't group by which entities use which texture. So I could be switching textures before drawing each entity! Is there a more efficient way to switch textures between entities? Or is glBindTexture() a good option?

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  • Entity Framework and distributed Systems

    - by Dirk Beckmann
    I need some help or maybe only a hint for the right direction. I've got a system that is sperated into two applications. An existing VB.NET desktop client using Entity Framework 5 with code first approach and a asp.net Web Api client in C# that will be refactored right yet. It should be possible to deliver OData. The system and the datamodel is still involving and so migrations will happen in undefined intervalls. So I'm now struggling how to manage my database access on the web api system. So my favourd approch would be us Entity Framework on both systems but I'm running into trouble while creating new migrations. Two solutions I've thought about: Shared Data Access dll The first idea was to separate the data access layer to a seperate project an reference from each of the systems. The context would be the same as long as the dll is up to date in each system. This way both soulutions would be able to make a migration. The main problem ist that it is much more complicate to update a web api system than it is with the client Click Once Update Solution and not every migration is important for the web api. This would couse more update trouble and out of sync libraries Database First on Web Api The second idea was just to use the database first approch an on web api side. But it seems that all annotations will be lost by each model update. Other solutions with stored procedures have been discarded because of missing OData support and maintainability. Does anyone run into same conflicts or has any advices how such a problem can be solved!

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  • Entity framework separating entities for product and customer specific implementation

    - by Codecat
    I am designing an application with intention into making it a product line. I would like to extend the functionality across all layers and first struggle is with domain models. For example, core functionality would have entity named Invoice with few standard fields and then customer requirements will add some new fields to it, but I don't want to add to core Invoice class. For every customer I could use customer specific DbContext and injected correct context with dependency injection. Also every customer will get they own deployment public class Product.Domain.Invoice { public int InvoiceId { get; set; } // Other fields } How to approach this problem? Solution 1 does not work since Entity Framework does not allow same simple name classes. public class CustomerA.Domain.Invoice : Product.Domain.Invoice { public User ReviewedBy { get; set; } public DateTime? ReviewedOn { get; set; } } Solution 2 Create separate table and link it to core domain table. Reusing services and controllers could be harder. public class CustomerA.Domain.CustomerAInvoice { public Product.Domain.Invoice Invoice { get; set; } public User ReviewedBy { get; set; } public DateTime? ReviewedOn { get; set; } }

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  • Entity Framework RC1 DbContext query issue

    - by Steve
    I'm trying to implement the repository pattern using entity framework code first rc 1. The problem I am running into is with creating the DbContext. I have an ioc container resolving the IRepository and it has a contextprovider which just news up a new DbContext with a connection string in a windsor.config file. With linq2sql this part was no problem but EF seems to be choking. I'll describe the problem below with an example. I've pulled out the code to simplify things a bit so that is why you don't see any repository pattern stuff here. just sorta what is happening without all the extra code and classes. using (var context = new PlssContext()) { var x = context.Set<User>(); var y = x.Where(u => u.UserName == LogOnModel.UserName).FirstOrDefault(); } using (var context2 = new DbContext(@"Data Source=.\SQLEXPRESS;Initial Catalog=PLSS.Models.PlssContext;Integrated Security=True;MultipleActiveResultSets=True")) { var x = context2.Set<User>(); var y = x.Where(u => u.UserName == LogOnModel.UserName).FirstOrDefault(); } PlssContext is where I am creating my DbContext class. The repository pattern doesn't know anything about PlssContext. The best I thought I could do was create a DbContext with the connection string to the sqlexpress database and query the data that way. The connection string in the var context2 was grabbed from the context after newing up the PlssContext object. So they are pointing at the same sqlexpress database. The first query works. The second query fails miserably with this error: The model backing the 'DbContext' context has changed since the database was created. Either manually delete/update the database, or call Database.SetInitializer with an IDatabaseInitializer instance. For example, the DropCreateDatabaseIfModelChanges strategy will automatically delete and recreate the database, and optionally seed it with new data. on this line var y = x.Where(u => u.UserName == LogOnModel.UserName).FirstOrDefault(); Here is my DbContext namespace PLSS.Models { public class PlssContext : DbContext { public DbSet<User> Users { get; set; } public DbSet<Corner> Corners { get; set; } public DbSet<Lookup_County> Lookup_County { get; set; } public DbSet<Lookup_Accuracy> Lookup_Accuracy { get; set; } public DbSet<Lookup_MonumentStatus> Lookup_MonumentStatus { get; set; } public DbSet<Lookup_CoordinateSystem> Lookup_CoordinateSystem { get; set; } public class Initializer : DropCreateDatabaseAlways<PlssContext> { protected override void Seed(PlssContext context) { I've tried all of the Initializer strategies with the same errors. I don't think the database is changing. If I remove the modelBuilder.Conventions.Remove<IncludeMetadataConvention>(); Then the error returns is The entity type User is not part of the model for the current context. Which sort of makes sense. But how do you bring this all together?

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  • Rails - Accessing model class methods from within ActiveRecord model

    - by aaronrussell
    I have a simple standalone model that doesn't inherit from ActiveRecord or anything else, called SmsSender. As the name suggests, it delivers text messages to an SMS gateway. I also have an ActiveRecord model called SmsMessage which has an instance method called deliver: def deliver SmsSender.deliver_message(self) self.update_attributes :status => "Sent" end The above is returning uninitialized constant SmsSender. I'm sure this is dead simple, but how can I access the SmsSender class from within my model?

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