type Confidence =
    | Low
    | Medium
    | High

type Goal = {
    Confidence: Confidence
    ...
 }

type UnionHandler<'T>() =
       inherit SqlMapper.TypeHandler<'T>()

       override __.SetValue(param, value) =
            param.Value <- value.ToString()
            ()

       override x.Parse(value: obj) =
            Union.parse <| string value


let registerTypeHandlers() =
    SqlMapper.AddTypeHandler (UnionHandler<Confidence>())