How to insert record with many to many relational tables

Question

work on asp.net mvc5 ef-6.Face problem with many to many relational table data insertion.My classes models are

public class Product
{
    public long ProductID { get; set; }
    public string ProductName { get; set; }

    //navigation property to Supplier
    public virtual ICollection<ProductSupplier> ProductSupplier { get; set; }
}

public class Supplier
{      
    public long SupplierID { get; set; }
    public string SupplierName { get; set; }

    // navigation property to Product
    public virtual ICollection<ProductSupplier> ProductSupplier { get; set; }
}

public class ProductSupplier
{
    public long ProductID { get; set; }
    public long SupplierID { get; set; }
    public virtual Product Product { get; set; }
    public virtual Supplier Supplier { get; set; }
    public bool IsActive { get; set; }  
}

How to insert records on above classes.Will first i need to insert on Product then Supplier then ProductSupplier.

Answer 1

You essentially just have a M2M with a payload here. With that, you'll need to set the Product / Supplier on ProductSupplier before saving that relationship. So something along these lines:

var product = new Product();
var supplier = new Supplier();
var productSupplier = new ProductSupplier
{
    Product = product,
    Supplier = supplier
};
db.ProductSuppliers.Add(productSupplier);
db.SaveChanges();

For simplicity, I only dealt with the relationships here. Obviously you'd want to intialize/add the other data on the entities. Also, note that it's only necessary to explicitly add the ProductSupplier instance to its DbSet . By virtue of being attached to that instance, the Product and Supplier instances will also be added and saved. You can of course still do that explicitly, instead, if you like.