MMPK m:n Relationships

Question

I see that at 100.4, QueryRelatedFeaturesAsync works with m:n relationships in a MMPK, at least in one direction.  However, it still fails in the reverse direction with an "Item not found in the database" exception.  Is this known behavior?

MarkCederholm · Answer

I figured it out!!!! QueryRelatedFeaturesAsync will not work if the FeatureLayer is a sublayer of a GroupLayer. Here's the example code: using System; using System.Collections.Generic; using System.IO; using System.Linq; using System.Text; using System.Threading.Tasks; using System.Windows; using Esri.ArcGISRuntime.ArcGISServices; using Esri.ArcGISRuntime.Data; using Esri.ArcGISRuntime.Mapping; using Esri.ArcGISRuntime.UI.Controls; namespace RelTest { static class MobileMapTest { static readonly bool bAddGroupLayers = true; const string sMMPKPath = @"C:\apps\FieldApp\Data"; static readonly string[] MMPKNames = { "AZLandbase.mmpk", "AZGas.mmpk" }; const int iMapIndex = 0; const int iRelID = 4; const string sForwardTableName = "RegulatorStation"; const int iForwardFeatureID = 2912; public static async Task OpenMMPK() { // Open mobile map MapView mv = MainWindowModel.Current.MapViewContainerContent; Map MyMap = new Map(); Viewpoint vp = null; foreach (string sMMPKName in MMPKNames) { string sMMPK = Path.Combine(sMMPKPath, sMMPKName); MobileMapPackage mmpk = await MobileMapPackage.OpenAsync(sMMPK); Map map = mmpk.Maps[iMapIndex]; if (vp == null) vp = map.InitialViewpoint; LayerCollection Sublayers; if (bAddGroupLayers) { GroupLayer gLyr = new GroupLayer() { Name = Path.GetFileNameWithoutExtension(sMMPKName), Id = Guid.NewGuid().ToString(), IsVisible = true }; MyMap.OperationalLayers.Add(gLyr); Sublayers = gLyr.Layers; } else Sublayers = MyMap.OperationalLayers; foreach (Layer lyr in map.OperationalLayers.ToList()) { map.OperationalLayers.Remove(lyr); Sublayers.Add(lyr); } } MyMap.InitialViewpoint = vp; mv.Map = MyMap; await MyMap.LoadAsync(); } public static async Task QueryTest() { // Get feature layer MapView mv = MainWindowModel.Current.MapViewContainerContent; FeatureLayer fLyr = FindLayer(mv.Map.OperationalLayers, sForwardTableName); if (fLyr == null) return; ArcGISFeatureTable fTab = fLyr.FeatureTable as ArcGISFeatureTable; // Get feature for forward test QueryParameters qp = new QueryParameters(); qp.ObjectIds.Add(iForwardFeatureID); FeatureQueryResult queryResult = await fTab.QueryFeaturesAsync(qp); ArcGISFeature feat = queryResult.FirstOrDefault() as ArcGISFeature; // Get forward M:N relationship RelationshipInfo relInfo = null; foreach (RelationshipInfo info in fTab.LayerInfo.RelationshipInfos) { if (info.Id != iRelID) continue; relInfo = info; break; } // Forward related query test // 100.5 BUG: This will fail if the feature layer is a sublayer of a group layer RelatedQueryParameters param = new RelatedQueryParameters(relInfo); bool bForwardSuccess = true; IReadOnlyList<RelatedFeatureQueryResult> Results = await fTab.QueryRelatedFeaturesAsync(feat, param); if (Results == null) bForwardSuccess = false; else if (Results.Count == 0) bForwardSuccess = false; else { RelatedFeatureQueryResult relResult = Results.FirstOrDefault(); bForwardSuccess = (relResult.Count() > 0); } StringBuilder sb = new StringBuilder(); sb.Append("Query test (with"); if (!bAddGroupLayers) sb.Append("out"); sb.Append(" group layers): "); if (bForwardSuccess) sb.Append("Success"); else sb.Append("Fail"); MessageBox.Show(sb.ToString()); } private static FeatureLayer FindLayer(IEnumerable<Layer> Layers, string sTableName) { foreach (Layer lyr in Layers) { if (lyr is FeatureLayer fLyr) { if (!(fLyr.FeatureTable is ArcGISFeatureTable fTab)) continue; if (fTab.TableName != sTableName) continue; return fLyr; } else if (lyr is GroupLayer gLyr) { FeatureLayer fl = FindLayer(gLyr.Layers, sTableName); if (fl == null) continue; return fl; } } return null; } } } ‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍‍

MarkCederholm · Answer

At 100.5, no m:n related features are returned at all from a mmpk.

Now my mmpk queries are working fine in both directions.  I don't know what I was doing wrong before.

Also, querying m:n related features from a service feature table exhibits interesting behavior:

1) If a related feature is found, multiple duplicate results are returned

2) If a related feature is not found, the query throws an "Item not found in database" exception

3) Nonetheless, the query does work in both directions, M>N and N>M.