public string OriginIDPropertyName {get;}

var create_rel = await QueuedTask.Run(() =>
{
  //Instantiate an operation for the Create
  var edit_op = new EditOperation()
  {
    Name = "Create a new relationship record",
    SelectNewFeatures = true
  };

  //Use datasets or feature layer(s) or standalone table(s)
  //Get a reference to the KnowledgeGraph
  //var kg = ... ; 

  //We will use a relate called 'HasEmployee' to relate an Organization w/ a Person
  //Use either tables or map members to get the rows to be related...
  var org_fc = kg.OpenDataset<FeatureClass>("Organization");
  var person_tbl = kg.OpenDataset<Table>("Person");

  //Get the relationship dataset
  //We can use either a table or standalone table
  var emp_tbl = kg.OpenDataset<Table>("HasEmployee");

  //we need the names of the origin and destination relationship properties
  var kg_prop_info = kg.GetPropertyNameInfo();

  //Arbitrarily use the first record from the two entity datasets "to be" related
  //Entities are always related by Global ID. Origin to Destination specifies the
  //direction (of the relate).
  //
  //Populate the attributes for the relationship
  var attribs = new Dictionary<string, object>();

  using (var rc = org_fc.Search())
  {
    if (rc.MoveNext())
      //Use the KnowledgeGraphPropertyInfo to avoid hardcoding...
      attribs[kg_prop_info.OriginIDPropertyName] = rc.Current.GetGlobalID();
  }
  using (var rc = person_tbl.Search())
  {
    if (rc.MoveNext())
      //Use the KnowledgeGraphPropertyInfo to avoid hardcoding...
      attribs[kg_prop_info.DestinationIDPropertyName] = rc.Current.GetGlobalID();
  }

  //Add any extra attribute information for the relation as needed
  attribs["StartDate"] = new DateTimeOffset(DateTime.Now);

  //Add a create for the relationship to the operation
  edit_op.Create(emp_tbl, attribs);

  //Do the create
  return edit_op.Execute();
});

var create_rel1 = await QueuedTask.Run(() =>
{
  //This example uses a chained edit operation
  var edit_op = new EditOperation()
  {
    Name = "Create entities and a relationship",
    SelectNewFeatures = true
  };

  //We are just going to use the GDB objects in this one but
  //we could equally use feature layers/standalone tables

  //using Feature Class/Tables (works within Investigation or map)
  var org_fc = kg.OpenDataset<FeatureClass>("Organization");
  var person_tbl = kg.OpenDataset<Table>("Person");
  //Relationship table
  var emp_tbl = kg.OpenDataset<Table>("HasEmployee");

  var attribs = new Dictionary<string, object>();

  //New Organization
  attribs["Name"] = "Acme Ltd.";
  attribs["Description"] = "Specializes in household items";
  attribs["SHAPE"] = org_location;

  //Add it to the operation - we need the rowtoken
  var rowtoken = edit_op.Create(org_fc, attribs);

  attribs.Clear();//we are going to re-use the dictionary

  //New Person
  attribs["Name"] = "Bob";
  attribs["Age"] = "41";
  attribs["Skills"] = "Plumbing, Framing, Flooring";

  //Add it to the operation
  var rowtoken2 = edit_op.Create(person_tbl, attribs);

  attribs.Clear();

  //At this point we must execute the create of the entities
  if (edit_op.Execute())
  {
    //if we are here, the create of the entities was successful

    //Next, "chain" a second create for the relationship - this ensures that
    //Both creates (entities _and_ relation) will be -undone- together if needed
    //....in other words they will behave as if they are a -single- transaction
    var edit_op_rel = edit_op.CreateChainedOperation();

    //we need the names of the origin and destination relation properties
    var kg_prop_info = kg.GetPropertyNameInfo();
    //use the row tokens we held on to from the entity creates
    attribs[kg_prop_info.OriginIDPropertyName] = rowtoken.GlobalID;
    attribs[kg_prop_info.DestinationIDPropertyName] = rowtoken2.GlobalID;

    //Add any extra attribute information for the relation as needed
    attribs["StartDate"] = new DateTimeOffset(DateTime.Now);

    //Do the create of the relate
    edit_op_rel.Create(emp_tbl, attribs);
    return edit_op_rel.Execute();
  }
  return false;//Create of entities failed
});

internal static string GetDocumentTypeName(KnowledgeGraphDataModel kg_dm)
{
  var entity_types = kg_dm.GetEntityTypes();
  foreach (var entity_type in entity_types)
  {
    var role = entity_type.Value.GetRole();
    if (role == KnowledgeGraphNamedObjectTypeRole.Document)
      return entity_type.Value.GetName();
  }
  return "";
}

internal static string GetHasDocumentTypeName(KnowledgeGraphDataModel kg_dm)
{
  var rel_types = kg_dm.GetRelationshipTypes();
  foreach (var rel_type in rel_types)
  {
    var role = rel_type.Value.GetRole();
    if (role == KnowledgeGraphNamedObjectTypeRole.Document)
      return rel_type.Value.GetName();
  }
  return "";
}

internal async void AddDocumentRecord()
{

  await QueuedTask.Run(() =>
  {
    using (var kg = GetKnowledgeGraph())
    {
      var edit_op = new EditOperation()
      {
        Name = "Create Document Example",
        SelectNewFeatures = true
      };

      var doc_entity_name = GetDocumentTypeName(kg.GetDataModel());
      if (string.IsNullOrEmpty(doc_entity_name))
        return false;
      var hasdoc_rel_name = GetHasDocumentTypeName(kg.GetDataModel());
      if (string.IsNullOrEmpty(hasdoc_rel_name))
        return false;

      //Document can also be FeatureClass
      var doc_tbl = kg.OpenDataset<Table>(doc_entity_name);
      var doc_rel_tbl = kg.OpenDataset<Table>(hasdoc_rel_name);

      //This is the document to be added...file, image, resource, etc.
      var url = @"E:\Data\Temp\HelloWorld.txt";
      var text = System.IO.File.ReadAllText(url);

      //Set document properties
      var attribs = new Dictionary<string, object>();
      attribs["contentType"] = @"text/plain";
      attribs["name"] = System.IO.Path.GetFileName(url);
      attribs["url"] = url;
      //Add geometry if relevant
      //attribs["Shape"] = doc_location;

      //optional
      attribs["fileExtension"] = System.IO.Path.GetExtension(url);
      attribs["text"] = System.IO.File.ReadAllText(url);

      //optional and arbitrary - your choice
      attribs["title"] = System.IO.Path.GetFileNameWithoutExtension(url);
      attribs["keywords"] = @"text,file,example";
      attribs["metadata"] = "";

      //Specify any additional custom attributes added to the document
      //schema by the user as needed....
      //attribs["custom_attrib"] = "Foo";
      //attribs["custom_attrib2"] = "Bar";

      //Get the entity whose document this is...
      var org_fc = kg.OpenDataset<FeatureClass>("Organization");
      var qf = new QueryFilter()
      {
        WhereClause = "name = 'Acme'",
        SubFields = "*"
      };
      var origin_org_id = Guid.Empty;
      using (var rc = org_fc.Search(qf))
      {
        if (!rc.MoveNext())
          return false;
        origin_org_id = rc.Current.GetGlobalID();//For the relate
      }

      //Create the document row/feature
      var rowtoken = edit_op.Create(doc_tbl, attribs);
      if (edit_op.Execute())
      {
        //Create the relationship row
        attribs.Clear();
        //we need the names of the origin and destination relation properties
        var kg_prop_info = kg.GetPropertyNameInfo();
        //Specify the origin entity (i.e. the document 'owner') and
        //the document being related to (i.e. the document 'itself')
        attribs[kg_prop_info.OriginIDPropertyName] = origin_org_id;//entity
        attribs[kg_prop_info.DestinationIDPropertyName] = rowtoken.GlobalID;//document

        //Specify any custom attributes added to the has document
        //schema by the user as needed....
        //attribs["custom_attrib"] = "Foo";
        //attribs["custom_attrib2"] = "Bar";

        //"Chain" a second create for the relationship - this ensures that
        //Both creates (doc _and_ "has doc" relation) will be -undone- together if needed
        //....in other words they will behave as if they are a -single- transaction
        var edit_op_rel = edit_op.CreateChainedOperation();
        edit_op_rel.Create(doc_rel_tbl, attribs);
        return edit_op_rel.Execute();
      }
    }
    return false;
  });
}

await QueuedTask.Run(() =>
{

  var edit_op = new EditOperation()
  {
    Name = "Modify an Entity and Relationship record",
    SelectModifiedFeatures = true
  };

  //We are  going to use mapmembers in this example
  //we could equally use feature classes/tables
  var kg_layer = mv.Map.GetLayersAsFlattenedList()?
                .OfType<ArcGIS.Desktop.Mapping.KnowledgeGraphLayer>().First();
  //Entity
  var org_fl = kg_layer.GetLayersAsFlattenedList().OfType<FeatureLayer>()
                  .First(child_layer => child_layer.Name == "Organization");
  //and/or Relationship
  var rel_stbl = kg_layer.GetStandaloneTablesAsFlattenedList()
                  .First(child_layer => child_layer.Name == "HasEmployee");

  //Get the entity feature to modify
  long org_oid = -1;
  var org_gid = Guid.Empty;
  var qf = new QueryFilter()
  {
    WhereClause = "name = 'Acme'",
    SubFields = "*"
  };
  using (var rc = org_fl.Search(qf))
  {
    if (!rc.MoveNext())
      return;
    org_oid = rc.Current.GetObjectID();
    org_gid = rc.Current.GetGlobalID();
  }
  if (org_oid == -1)
    return; //nothing to modify

  var attribs = new Dictionary<string, object>();

  //Specify attributes to be updated
  attribs["Name"] = "Acme Ltd.";
  attribs["Description"] = "Specializes in household items";
  attribs["SHAPE"] = org_updated_location;

  //Add to the edit operation
  edit_op.Modify(org_fl, org_oid, attribs);

  //Get the relationship record (if a relate is being updated)
  //we need the name of the origin id property
  var kg_prop_info = kg.GetPropertyNameInfo();
  var sql = $"{kg_prop_info.OriginIDPropertyName} = ";
  sql += "'" + org_gid.ToString("B").ToUpper() + "'";

  qf = new QueryFilter()
  {
    WhereClause = sql,
    SubFields = "*"
  };
  long rel_oid = -1;
  using (var rc = rel_stbl.Search(qf))
  {
    if (!rc.MoveNext())
      return;
    rel_oid = rc.Current.GetObjectID();
  }
  if (rel_oid > -1)
  {
    //add the relate row updates to the edit operation
    attribs.Clear();//we are going to re-use the dictionary
    attribs["StartDate"] = new DateTimeOffset(DateTime.Now);
    attribs["custom_attrib"] = "Foo";
    attribs["custom_attrib2"] = "Bar";
    //Add to the edit operation
    edit_op.Modify(rel_stbl, rel_oid, attribs);
  }
  //do the update(s)
  if (edit_op.Execute())
  {
    //TODO: Operation succeeded
  }

});