Synchronization code

Src/Asp.NetCore2/SqlSugar/ExpressionsToSql/ResolveItems/OneToManyNavgateExpressionN.cs

@@ -226,10 +226,6 @@ namespace SqlSugar
             BidColumn = item.ThisEntityInfo.Columns.FirstOrDefault(it => it.IsPrimarykey);
             AidColumn = item.ParentEntityInfo.Columns.FirstOrDefault(it => it.IsPrimarykey);
 
-            if (item.Nav.MappingType == null) 
-            {
-                return null;
-            }
             var abEntity =this.context.EntityMaintenance.GetEntityInfo(item.Nav.MappingType);
             var Ab_Aid = abEntity.Columns.FirstOrDefault(it => item.Nav.MappingAId == it.PropertyName);
             var Ab_Bid = abEntity.Columns.FirstOrDefault(it => item.Nav.MappingBId == it.PropertyName);