Check if Record Exists in Entity Framework

Question

Could somebody please tell me how I check to see if a record exists, if it does exists then do nothing and if it doesn't then add the record to the database?

Please see my code below:

if (isIpnValidated == true)
{
    using (WebApplication1Entities db = new WebApplication1Entities())
    {
        Orders order = new Orders();
        order.UserId = userId;
        order.Date = System.DateTime.Now;
        order.Transaction = txnId;
        order.Amount = Convert.ToDecimal(mcGross);
        order.Email = payerEmail;
        order.Country = residenceCountry;

        db.Orderss.Add(order);
        db.SaveChanges();
    }
}

I just want to ensure no possible duplication in the database.

Apologies, I want to ensure the txnId does not already exist. — iggyweb, May 14 '14 at 12:00
Your question is entirely unrelated to ASP.NET MVC. Your code looks like you were using Entity Framework though. Did you mean EF 5? — chiccodoro, May 14 '14 at 12:01
I cannot use Any with this function, I can use Find, Add, AddRange, etc... but not Any unfortunately. — iggyweb, May 14 '14 at 12:05
I am using Visual Studio 2013 and if I type db.Orders. Any does not appear in the list and if I add it manually I get a red underline under the word Any. — iggyweb, May 14 '14 at 12:07
@iggyweb Then you're missing a reference to `System.Linq`. Add it to the top of your file, or get Resharper ;) — CodingIntrigue, May 14 '14 at 12:07
@iggyweb Using sroes answer below, but you should start learning Linq syntax first. — CodingIntrigue, May 14 '14 at 12:13
Please refer this SO Answer[1]. [1] https://stackoverflow.com/questions/21302244/check-if-a-record-exists-in-the-database/61420866#61420866 — Senthuran, Apr 25 '20 at 04:14

score 70 · Accepted Answer · edited Jun 07 '21 at 22:08

70

Use Any:

if (isIpnValidated)
{
    using (WebApplication1Entities db = new WebApplication1Entities())
    {
        if (db.Orderss.Any(o => o.Transaction == txnId)) return;

        Orders order = new Orders();
        order.UserId = userId;
        order.Date = System.DateTime.Now;
        order.Transaction = txnId;
        order.Amount = Convert.ToDecimal(mcGross);
        order.Email = payerEmail;
        order.Country = residenceCountry;

        db.Orderss.Add(order);
        db.SaveChanges();
    }
}

edited Jun 07 '21 at 22:08

hastrb

410
4
12

answered May 14 '14 at 12:05

sroes

14,663
1
53
72

1

This assumes he doesn't want to update an existing record... – Maess May 14 '14 at 12:06
10

Yes, see his question: "if it does exists then do nothing" – sroes May 14 '14 at 12:08
1

I definitely don't want to update, only add if the txnId does not exist. – iggyweb May 14 '14 at 12:08
1

Can I please ask one more thing, how do I check to see if a order actually exists for a user and todays date, I've tried `if (db.Orderss.Any(o => o.UserId == userId && o.Date == System.DateTime.Now)) return;` but it doesn't appear to work. – iggyweb May 15 '14 at 13:07
3

What about `if (db.Orderss.Any(o => o.UserId == userId && o.Date.Date == System.DateTime.Today)) return;`? – sroes May 15 '14 at 13:10
This is very bad. It can cause bugs if used concurrently!! Just think what happens if someone inserts an order like that between `Any` and `SaveChanges`. You will have 2 duplicate orders. – Konrad Feb 20 '19 at 14:59

Maess · Answer 2 · 2019-10-31T16:07:19.777

3

using (WebApplication1Entities db = new WebApplication1Entities())
{
   var order = db.Orders.GetAll().Where(x=> x.Transaction == txnId).FirstOrDefault();
   if(order != null) // update
   {
      //.....
      db.SaveChanges();
    }
   else
   {
      // new
   }
}

edited Oct 31 '19 at 16:07

answered May 14 '14 at 12:05

Maess

4,118
20
29

No, since he is going to work with order, no need to run the statement twice. – Maess May 14 '14 at 12:06
1

Do you realize you just queried all the orders in the table when you only need one? There is no need for the GetAll() – makinyelure Oct 07 '22 at 15:46
Besides he is getting all columns , There is no need to FirstOrDefault either , just use count() – Vahid2023 May 29 '23 at 15:15

Check if Record Exists in Entity Framework

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