> For the complete documentation index, see [llms.txt](https://jen-hsuan-hsieh.gitbook.io/asp-net/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://jen-hsuan-hsieh.gitbook.io/asp-net/chapter1/1.1.the-complete-asp.net-mvc-5-course/13working-with-data/135overriding-conventions.md).

# 1.3.5.Overriding conventions

* 1. To limit column to non-nullable, modify the code:

```
namespace Vidly2.Models
{
    public class Customer
    {
        public int Id{ get; set; }
        [Required]
        [StringLength(255)]
        public string Name { get; set; }
        public bool IsSubscribeToNesletter { get; set; }
        public MembershipType membershipType { get; set; }
        public byte membershipTypeId { get; set; }
    }
}
```

* 2.Update database:

  ```
    `update-database`
  ```