EF issue - user is a value type and cannot be selected from

[bobloblaws93]

Hi, all I'm having a bit of an issue with graphql. I'm trying to query my dataset but im running into problems the moment I try execute a query. I get the exeception:

GraphQL.Parser.SourceException: 'field ``user'' is a value type and cannot be selected from'

My code is as follows:

   public void test() {
         var schema = GraphQL<AdtDbContext>.CreateDefaultSchema(() => new AdtDbContext());
         schema.AddType<NTC_TC_MAINS>().AddAllFields();            
         var gql = new GraphQL<AdtDbContext>(schema);
         schema.AddField("user", new { NAME = "-1" }, (db, args) => db.NTC_TC_MAINS.SingleOrDefault(u => u.TC_NAME == args.NAME));
         schema.Complete();
         var qresult = gql.ExecuteQuery("{user(NAME:\"Hudson\") {tC_NAME}}");
         Console.WriteLine(JsonConvert.SerializeObject(qresult, Formatting.Indented));
        }

With the following DBset: public DbSet<NTC_TC_MAINS> NTC_TC_MAINS { get; set; }

The exception is as follows is as follows: GraphQL.Parser.SourceException occurred HResult=0x80131500 Message=field ``user'' is a value type and cannot be selected from Source=GraphQL.Parser StackTrace:

Any advice into solving this would be greatly helpful!

[chkimes]

What's the query you're running? Is NTC_TC_MAINS a class or a struct?

[bobloblaws93]

Thanks for Replying! NTC_TC_MAINS is a class as is defined as follows:

namespace ATD.Domain.Entities
{
    [Table("NTC_TC_MAINS")]
    public class NTC_TC_MAINS
    {
        [Key]
        [MaxLength(100)]
        public string ID { get; set; }
        [Required]
        [MaxLength(1000)]
        public string TC_NAME { get; set; }
        [Required]
        public int TC_TYPE_ID { get; set; }
        [Required]
        public int TC_SUB_TYPE_ID { get; set; }
        [Required]
        public int TC_CERT_TYPE_ID { get; set; }
        [MaxLength(200)]
        public string TC_CERT_DOC { get; set; }
        [MaxLength(200)]
        public string TC_LOGO { get; set; }
        [MaxLength(4000)]
        public string TC_VISION { get; set; }
        [MaxLength(4000)]
        public string TC_DESC { get; set; }
        [Required]
        public int TC_AFFI_ID { get; set; }
     }
}

The main query im trying to run is to find any NTC_TC_MAIN with the name "Hudson".

    {
     user(NAME:\"Hudson\") 
      {
        tC_NAME,tC_LOGO,tC_VISION
      }
    }

I was running into a similar issue as #49, where I inherited a database with names that are all uppercased.

I don't know if it helps but everything works fine the moment I I grab a list and instantiate a new context like so, it works:

        class Context
        {
            public IList<NTC_TC_MAINS> ntc { get; set; }
        }

        public void test()
        {
            List<NTC_TC_MAINS> allTCs = null;
            using (AtduDbContext context = new AtduDbContext())
            {
                allTCs = context.NTC_TC_MAINS.Select(t => (t)).ToList();

                var schema = GraphQL<Context>.CreateDefaultSchema(() =>
                    new Context
                    {
                        ntc = allTCs
                    });
                schema.AddType<NTC_TC_MAINS>().AddAllFields();
                schema.AddField("user", new { NAME = "-1" }, (C, args) => C.ntc.SingleOrDefault(u => u.TC_NAME == args.NAME));
                schema.Complete();
                var gql = new GraphQL<Context>(schema);
                var qresult = gql.ExecuteQuery("{user(NAME:\"Hudson\") {tC_NAME,tC_LOGO,tC_VISION}}");
                System.Diagnostics.Debug.Write("graphsqlul" + (JsonConvert.SerializeObject(qresult, Formatting.Indented)));
            }

But I don't want to call and grab the entire list all the time. Would rather be able to run the graphQL query and filter based on that.

[chkimes]

Can you try using FirstOrDefault?

[bobloblaws93]

changed to: schema.AddField("user", new { id = "-1" }, (db, args) => db.NTC_TC_MAINS.Where(u => u.TC_NAME == args.id).FirstOrDefault()); Still gives me the same exception though

[chkimes]

AddField should return a GraphQLFieldBuilder. Can you assign that to a variable and inspect the private fields in the debugger (expand the _field field and its Type property), then paste the results here?

On Tue, Mar 27, 2018 at 10:49 AM ronnpang1 notifications@github.com wrote:

changed to: schema.AddField("user", new { id = "-1" }, (db, args) => db.NTC_TC_MAINS.Where(u => u.TC_NAME == args.id).FirstOrDefault()); Still gives me the same exception though

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[bobloblaws93]

Expanding the _fields gives: Expanding the type yields:

[chkimes]

So the immediate issue is that type.IsScalar is true, which is definitely not correct. I'll have to think some on why that could be.

Is it possible that NTC_TC_MAINS is defined twice in your project, and that the one used in schema.AddType<NTC_TC_MAINS>().AddAllFields(); is not the same as the one used in db.NTC_TC_MAINS?

On Tue, Mar 27, 2018 at 11:25 AM ronnpang1 notifications@github.com wrote:

Expanding the _fields gives: [image: prnt1] https://user-images.githubusercontent.com/4573812/37977293-717b3b4c-31b1-11e8-88c6-8a76a44e7826.png Expanding the type yields: [image: prnt2] https://user-images.githubusercontent.com/4573812/37977325-7c7c1b74-31b1-11e8-97ae-78f69125e348.png

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[bobloblaws93]

Oh man, you were absolutely right, NTC_MAIN was defined twice accidentally. Everything works now, thank you so much!