ASP.NET C# Class/Object with default values and database NOT NULL columns

Question

I am using SQL server for database while developing in ASP.NET . In my database table, most of the columns are NOT NULL and have a set default value. I am also using Entity Framework.

My Model(class) currently looks like this:

public partial class INV
{
    [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Usage", "CA2214:DoNotCallOverridableMethodsInConstructors")]
    public INV()
    {
        this.INVAttachments = new HashSet<INVAttachment>();
    }

    public int ID { get; set; }
    public string SUPPROD { get; set; }
    public string TYPE1 { get; set; }
    public int MAXQTY { get; set; }
    public decimal ROP { get; set; }
    public int ROQ { get; set; }
    public decimal SSL { get; set; }
    public Nullable<System.DateTime> SYSDATE { get; set; }
    public Nullable<System.DateTime> MAINT_DATE { get; set; }


    [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Usage", "CA2227:CollectionPropertiesShouldBeReadOnly")]
    public ICollection<INVAttachment> INVAttachments { get; set; }
}

The user submits a form, and inside the form, most of fields are actually optional. But in the database, the columns are not null.

When I POST the form over to the server side, the INV object representation has null for the properties of the INV object. Below is a WebAPI function to handle the POST and save the INV object in the database.

    [ResponseType(typeof(string))]
    public async Task<string> PostINV(INV iNV)
    {
        try
        {
            if (!ModelState.IsValid)
            {
                //return BadRequest(ModelState);
                return "badRequest";
            }

            db.INVs.Add(iNV);
            await db.SaveChangesAsync();

            //codes written here


        }catch (Exception ex)
        {
            return "";
        }
    }

The above function is now returning system.data.entity.validation.dbvalidationerror for the INV entity because the properties for INV is required, but the object that I POST over contain NULL values.

My question is it possible to make sure the database columns remain NOT NULL but at the same time, I don't want my Model or Class to use Nullable types? Is it a matter of using a constructor for my class to set default values ?

Well you have a problem. you have a constraint on your DB to enforce a value, and your model accepts nulls. You are either going to have to make up values for your DB, make your db fields nullable, or enforce the constraint on the user form. .Net or SQL will not be able to read your mind — TheGeneral
– TheGeneral, Commented Aug 6, 2018 at 3:21
@TheGeneral, how does one make up values for DB ? Is it done by defining a constructor or a method on the model? — jin cheng teo
– jin cheng teo, Commented Aug 6, 2018 at 3:41
Are you using Code-First, or is this a Database-first model using an EDMX file? — Tieson T.
– Tieson T., Commented Aug 6, 2018 at 5:29

TheGeneral · Accepted Answer · 2018-08-06 03:46:54Z

1

This is just an answer to your question in a comment, and may not be the best solution

how does one make up values for DB ? Is it done by defining a constructor or a method on the model?

You can do it a number of ways, however this is a very simple solution

public class Track
{
    public Track()
    {
        LengthInMeters = 400;   
    }

    public int LengthInMeters { get; set; }        
}

answered Aug 6, 2018 at 3:46

TheGeneral

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2 Comments

H.Mikhaeljan Over a year ago

Lets make it even simpeler public int LengthInMeters { get; set; } = 400;

TheGeneral Over a year ago

@H.Mikhaeljan perfect :)

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