entity-framework-4.1

I have been studying the EF for a short time and cant find the answer to this question. I have existing database and I am using CodeFirst to create classes for the model. What is the difference in using Attributes and EntityTypeConfiguration to define parameters of table columns? Since the database already has defined foreign keys and unique constraints, and so on, how and where to implement the validation for a best and most fluid result for use in ASP.NET MVC3? Is it better to implement Attributes and CustomValidation or to use TryCatch blocks to catch errors from db? Does Validator

Is it possible to create a One-to-Many relationship with Code First that uses a link/join table between them? public class Foo { public int FooId { get; set; } // ... public int? BarId { get; set; } public virtual Bar Bar { get; set; } } public class Bar { public int BarId { get; set; } // ... public virtual ICollection<Foo> Foos { get; set; } } I want this to map as follows: TABLE Foo FooId INT PRIMARY KEY ... TABLE Bar BarId INT PRIMARY KEY TABLE FooBar FooId INT PRIMARY KEY / FOREIGN KEY BarId INT FOREIGN KEY With this, I would have the ability to make sure Foo only has one Bar, but that

If I have the below class: public class Foo() { public int PropertyIWantUpdated {get; set;} public int PropertyIDontWantUpdated (get; set} public ICollection<Bar> Bars {get; set;} } When saving to my db, instead of context.Entry(thisFoo).State = EntityState.Modified; I'm using context.Entry(thisFood).Property(tf => tf.PropertyIWantUpdated).IsModified = true; how can I also save changes to Bars? Ladislav Mrnka It depends what you are trying to update. First of all let me clarify one important fact - if you have detached entity graph (more entities with relation) and you want to pass all changes

I'm writing an audit trail from snippets of code found online. On the call to my SaveChanges function I loop through all the modified entities registered with the Context and build log entries from their changes. foreach (DbEntityEntry modifiedEntity in this.ChangeTracker.Entries().Where(p => p.State == System.Data.EntityState.Added || p.State == System.Data.EntityState.Deleted || p.State == System.Data.EntityState.Modified)) { // For each changed record, get the audit record entries and add them foreach(AuditLog x in GetAuditRecordsForChange(modifiedEntity, userId)) { this.AuditLog.Add(x); }

Using the code-first approach available in the new 4.1 RC. Is there any way to persist the current data stored in a database when the mode changes? The database is created by the entity framework, and usually the database is dropped and recreated on model changes. Obviously as soon as the model is changed it will not be possible to use the context object to connect to the database to retrieve the data, so what are the options? Code first doesn't support database migration / evolution yet. If you want to do incremental DB development use model first (EDMX) with DbContext Generator T4 template

I have a WCF Data Service running on top of a Entity Framework code first 4.1 provider. The database is quite large (one key table has 77+ million records and grows by ~10% per month) and has presented quite a performance problem. While sharding a database that large is a pain it seems inevitable. My question is, has anybody successfully implemented EF with a sharded database and, if so, do you have any guidance? Have you investigated the following options: Clustering your DB (I assume it's SQL Server you are using)? Extracting some of your data (archived records, for example) into another