If I understand you correctly, you’re trying to eagerly load a complex property after establishing a relationship via a foreign key property. SaveChanges() does not do anything in the way of loading complex properties. At most, it is going to set your primary key property if you’re adding new objects. Your line reward = context.Set<Reward>().SingleOrDefault(a … Read more
Logging and Intercepting Database Operations article at MSDN is what your are looking for. The DbContext.Database.Log property can be set to a delegate for any method that takes a string. Most commonly it is used with any TextWriter by setting it to the “Write” method of that TextWriter. All SQL generated by the current context … Read more
The Entity Data Model Wizard’s Code First from Database does an excellent job creating your entity classes, as if they were created in the Code First style. What you are asking is if there is any way to keep these classes up-to-date as your database changes, similar to the EDMX style “Update Model From Database”. … Read more
This is not supported as per the specifications of version 6. This should throw a DbConcurrencyException exception saying A second operation started on this context before a previous asynchronous operation completed. Use ‘await’ to ensure that any asynchronous operations have completed before calling another method on this context. Any instance members are not guaranteed to … Read more
I faced a similar situation where we had a large database with many tables 7- 10 million records each. we used Entity framework to display the data. To get nice performance here’s what I learned; My 10 Golden rules for Entity Framework: Understand that call to database made only when the actual records are required. … Read more
I noticed that there is no need for copying. Apparently when adding an instance of a model to the database (even if the ID is set to one that already exists in the database), Entity Framework inserts a new row in the database and auto-increments it’s primary key. So this functionality is already built-in into … Read more
If you see the generated migration code you will see AddColumn AddColumn(“dbo.report”, “newProperty”, c => c.String(nullable: false)); You can add defaultValue AddColumn(“dbo.report”, “newProperty”, c => c.String(nullable: false, defaultValue: “old”)); Or add defaultValueSql AddColumn(“dbo.report”, “newProperty”, c => c.String(nullable: false, defaultValueSql: “GETDATE()”));
With EF6 and the DbContext API (for SQL Server), I’m currently using this piece of code: try { // Some DB access } catch (Exception ex) { HandleException(ex); } public virtual void HandleException(Exception exception) { if (exception is DbUpdateConcurrencyException concurrencyEx) { // A custom exception of yours for concurrency issues throw new ConcurrencyException(); } else … Read more
The simplest is to use FirstOrDefaultAsync or SingleOrDefaultAsync instead: model.Item = await db.Items.Include(i => i.ItemVerifications) .FirstOrDefaultAsync(i => i.Id == id.Value); The reason you are getting the error is because Find / FindAsync methods are defined for DbSet<T>, but the result of Include is IQueryable<T>. Another way is to combine FindAsync with explicit loading: model.Item = … Read more
Since EF doesn’t handle it automatically, yes, this is the recommend way. I suggest some modifications in article that you provided. Rename your enum public enum FacultyEnum { Eng, Math, Eco } Create a class that represent the table public class Faculty { private Faculty(FacultyEnum @enum) { Id = (int)@enum; Name = @enum.ToString(); Description = … Read more