I have a SharePoint 2013 list and want to use 2 columns as sort of a natural key on the list, so when a user enters a new entry, if these 2 columns combined match an entry already in the list, it won't add it.

Can I do this with a validation formula, or will I need to wire this check into an event receiver? If I can do it with validation, can anyone offer help on the validation forumla? I'm not overly familiar with the syntax.

[UPDATE]: I'm going to mark sasisprite's answer as correct, as his directly answers my question, but I wanted to leave an update on how I did this, in case anyone else comes across it looking to the same thing.

The solution is actually pretty simple, as I already had an event receiver wired into the list, I just had to add a method to check for a duplicate and return an error if that method returned true. So it looks like this:

public bool IsDuplicateEntry(string date, string sitename)
        string spUrl = "http://intranet";
        string spWeb = "myWeb";

        using (SPSite site = new SPSite(spUrl))
        using (SPWeb web = site.OpenWeb(spWeb))
            SPList list = web.Lists["My List"];
            foreach(SPListItem item in list.Items)
                string _name = item["Name"].ToString();
                string _date = DateTime.Parse(item["Date"].ToString()).ToString("d");
                if(_sitename == sitename && _date == date)
                    return true;
            return false;

So then it's just a matter of calling the method in my event receiver:

public override void ItemAdding(SPItemEventProperties properties)

            string theName = properties.AfterProperties["Name"].ToString());
            //I want to extract just the date here
            string theDate = DateTime.Parse(properties.AfterProperties["Date"].ToString()).ToString("d")

            if(IsDuplicateEntry(theName, theDate)
                  properties.Status = SPEventReceiverStatus.CancelWithError;
                  properties.ErrorMessage = "You have already made an entry for today");
                //Do your stuff

Hope this helps somebody.


Even I have the same requirement. But Unfortunately we don't have any option like enforcing unique by combining 2 columns by default.

Even I have researched a lot. But we can achieve this by using only info-path form.

Hope the below link may help you


  • Thanks for the answer. I was afraid of that. I'm already running an event receiver on the list, so I can add the check there. Would have saved me some time though to do it through a quick validation script. – gev125 Jan 26 '16 at 14:37

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