Need to know which chars you use for an _id. Looks like a-z, 0-9. But I need to make sure this is so, and in particular you do not use “/” and “,” to generate a Primary Key. It´s for a string lookup fuction, where I use above “/” and “,” to seperate fields and entries.
I believe they’re UUID’s so no common delimiters in any ids. But if you wanna go the extra mile you can always come up with some obnoxious looking Regex jic 
Thanks David.