creating a selector for document's name

Question

I am using CouchDB v3.1.0 and am trying to create a selector for /{db}/_find to find documents named "foobar".

In the docs section 1.3.6.1.1 Selector Basics, there are several mentions of a $title:

"selector": {
  "$title": "Live And Let Die"
}

However, when I try to use it like so:

curl -X POST -H "Content-Type: application/json" \
http://my-host-machine:5984/testdb/_find \
-d '{"selector":{"$title":"foobar"}}' --user admin | jq .

The following error message is output:

{
  "error": "invalid_operator",
  "reason": "Invalid operator: $title"
}

What does work is using the _id field in the selector: '{"selector":{"_id":"foobar"}}'

However, this doesn't feel correct to use a document's unique identifier. My questions:

• Does $title work? (Am I just using it incorrectly)
• Is _id an appropriate method?

Answer 1

If a name field has a dollar sign ($) prefix, CouchDB interprets it as an operator. $title however isn't a valid operator and the related selector samples in the documentation seem to be wrong.

On the other hand, when you need to select documents by a field that is preceded by a dollar sign ($), this answer may be useful.