Adding New Property to an existing model

Question

Hi,

I have implemented an asp.net web API with the code first approach. Now I need to add a property to some of the models. I alter the DB table and add a field, I got this error:

System.InvalidOperationException HResult=0x80131509 Message=The model backing the 'GameContext' context has changed since the database was created. Consider using Code First Migrations to update the database (http://go.microsoft.com/fwlink/?LinkId=238269). Source=<Cannot evaluate the exception source> StackTrace: <Cannot evaluate the exception stack trace>

I googled and came across adding below to the global.asax:

Database.SetInitializer<ApplicationDbContext>(null);

I wonder is it OK to use this on the production? Any suggestions would be great.

Thanks in advance.

Answer 1

@Cenk , based on my test, you could try the following steps to add a new property to a model and the related database.

First, Please add the property in the model class.

 public class Student  
        {  
            [Key]  
            public int ID { get; set; }  
      
            public string Name { get; set; }  
            public int Age { get; set; }  
      
            public string Address { get; set; }  
      
            public int Score { get; set; }    // Added property  
      
      
        }  

Second, Please execute the following commands in sequence in the Package Console below.

Enable-Migrations   
  
Add-Migration AddFileld  
  
Update-Database  

Finally, you could see the results in the code and database.

Code:

public partial class AddFileld : DbMigration  
    {  
        public override void Up()  
        {  
            AddColumn("dbo.Students", "Score", c => c.Int(nullable: false));  
        }  
          
        public override void Down()  
        {  
            DropColumn("dbo.Students", "Score");  
        }  
    }  

Result:

---

If the answer is the right solution, please click "Accept Answer" and kindly upvote it. If you have extra questions about this answer, please click "Comment".
Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.