Hi Steve, A couple of things to consider. You mention working with an 'entity selection' but then get into talking about collections. To create a collection from an entity selection, or only some properties of it, take a look at .toCollection(). https://doc.4d.com/4Dv18R3/4D/18-R3/entitySelectiontoCollection.305-4900500.en.html
This might give you want you want right there as you pass a comma delimited string to the method. The other approach is to simply do a query for what you need. These are really fast in ORDA thanks to a lot of optimization built in and it's very flexible. https://doc.4d.com/4Dv18R3/4D/18-R3/dataClassquery.305-4900853.en.html The old way of approaching these sorts of situations where you paid a big performance hit for multiple searches isn't nearly so true now. But it depends on your data. Try it and see. On Mon, May 11, 2020 at 9:04 PM Steve Slanec via 4D_Tech < [email protected]> wrote: > I'm trying come up with generic code that produces a projection from an > entity selection, and I think must be missing something obvious. I’d like > to perform the following statement: > > $collection:=$employees.company.country > > But as generic code. I want to be able to pass the ORDA path > “company.country” as a text variable so that I can change it at runtime. > > Obviously, using square bracket notation doesn’t work because square > brackets for entity selections are used for indexes: > > $collection:=$employees[“company.country”] // Syntax error > > So how can I do this? > > I guess I could write a method that splits the ORDA path into tokens, > examines each token individually, and traverses through relations if the > token kind is a “relation" until we get to the last token, whose kind must > be “storage". But I’m hoping I’m just being ignorant - it seems like a lot > of work for doing what object notation does so simply and elegantly. > > Using 4D v18, macOS 10.14 > > Thanks for any advice! > > - Steve > > > > Steve Slanec > Slanecon Digital > > ********************************************************************** > 4D Internet Users Group (4D iNUG) > New Forum: https://discuss.4D.com > Archive: http://lists.4d.com/archives.html > Options: https://lists.4d.com/mailman/options/4d_tech > Unsub: mailto:[email protected] > ********************************************************************** -- Kirk Brooks San Francisco, CA ====================== ********************************************************************** 4D Internet Users Group (4D iNUG) New Forum: https://discuss.4D.com Archive: http://lists.4d.com/archives.html Options: https://lists.4d.com/mailman/options/4d_tech Unsub: mailto:[email protected] **********************************************************************
