How do I map multiple lists with dapper

Question

I\'ve got three classes User, Order & Project which are stored in single tables. The orders and projects both have a n:n relation with the users. To implement that I\'ve got

Answer 1

I also had trouble coming to grips with the fact that Dapper doesn't do this automatically.

First, I'm not sure about comma-separated values for "splitOn." I thought you could only have one value there. So I have multiple columns in my result set named "ID" for example.

Second, to get the proper 1:N relationships you need to do an extra manual step. For example, I did a 2-table join of participants and their phone numbers. Then I had to do this:

private List<Participant> CollapseResultSet(List<Participant> rawdataset)
{
    List<Participant> ret = new List<Participant>();
    if (!rawdataset.Any())
    {
        return ret;
    }
    else
    {
        List<string> partIds = rawdataset.Select(p => p.ID).Distinct().ToList();
        foreach (string pId in partIds)
        {
            Participant tmp = rawdataset.Where(p => p.ID == pId).FirstOrDefault();
            tmp.PhoneNumbers = rawdataset.Where(p => p.ID == pId).Select(n => n.PhoneNumbers[0]).ToList();
            ret.Add(tmp);
        }
        return ret;
    }
}

Hope that helps.