EF Related Objects Filter Performance, use as IQueryable RRS feed

  • Question

  • Hi There!

    I've been working with EF for a while, and while I find it great, there's something that struggles my mind.

    Let's say I'm talking about the classic Order / OrderDetails relationship. DbContext generated and everything. Among other properties, I have a navigation property ICollection<OrderDetail> OrderDetails inside class Order.

    Now, what I can't understand, is why there is no clean way to use that navigation property as an IQueryable property. That way, I could make something like this with good performance, running the WHERE on SQL side:

    var argDetails = order.OrderDetails.Where(d => d.Active==true);

    or even...


    Instead, this fetches all the related details into memory and filters/counts using EntityToObjects.

    Totally not performant.

    Any good reason behind this?


    Wednesday, December 4, 2013 2:51 PM


  • Hello,

    >>is why there is no clean way to use that navigation property as an IQueryable property

    For this, we can have a try to define the navigation property OrderDetails inside class Order like below:

    public partial class Order
            public int OrderID { get; set; }
            public string OrderCode { get; set; }
            public string OrderName { get; set; }
            public virtual IQueryable<OrderDetail> OrderDetails { get; set; }

    Then we could use query like below:

    IQueryable<Order> order = db.Orders.Where(o => o.OrderID == 1);

    var result = order.Select(o => o.OrderDetails.Where(od => od.OrderDetailID == 1));

    So that the result will be IQueryable<T> type.

    If this does not work for you, please let me know.


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    Thursday, December 5, 2013 5:58 AM