Map only the selected columns when using EntityFramework

Question

In my recent Entity Core project I am having database table called "YmPlant" and it has 20+ columns. But for my requirement I just need data only from 3 columns. Also I am not required to do the write operations. Only read from YmlPlant table.

Just I need to know is it required to map all columns (20 +) inside the "OnModelCreating" method for YmlPlant table. Either it is working with mapping only the required 3 columns ?

Thanks
Nuwan

Answer 1

on model class you can use attribute

 [NotMapped]  
 public int ProductDiscountValue { get; set; }      

or on model binding event use Fluent API to ignore not required columns

protected override void OnModelCreating(ModelBuilder modelBuilder)  
{  
    modelBuilder.Entity<ymlPlant>()  
       .Ignore(t => t.columnname);        
}  

see more on EF Core Fluent API

Answer 2

As @AgaveJoe indicated create a class with that is needed e.g. I have a Customer model and to get only what is needed I created CustomerItem which in turn we use the following to get data back,

public static async Task<List<CustomerItem>> CustomerItems()  
{  
    await using var context = new Context();  
    return await context.Customers.AsNoTracking().Select(x => new CustomerItem()  
    {  
        CustomerIdentifier = x.CustomerIdentifier,   
        CompanyName = x.CompanyName,  
        ContactId = x.ContactId  
    }).ToListAsync();  
}