text box value in mvc5

Hi, I am using EF. I got an error, validation failed for one or more entities see entityvalidationerrors property for more details. here is my code.
if (list.Count > 0)
{
if (ModelState.IsValid)
{
external_applications ea = new external_applications();
ea.loginURL_development = dbAppEdit_old.loginURL_development;
ea.loginURL_production = dbAppEdit_old.loginURL_development; ea.registrationURL_development = dbAppEdit_old.registrationURL_development; ea.registrationURL_production = dbAppEdit_old.registrationURL_development; db.external_applications.Add(ea); //db.external_applications.Attach(application_new); db.Entry(ea).State = System.Data.Entity.EntityState.Modified; //db.external_applications.Find(application_new.description); db.SaveChanges();
}
}

Pass that value for two columns when updating the database. Something like this, 


SqlCommand command = new SqlCommand("UPDATE table_name SET column1 = @value, column2 = @value", conn);
command.Parameters.Add("@value", textBox1.Text);


Now when this would execute, both the columns would have similar value.