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Parameters

$1, $2, $3, ... are placeholders. They're substituted at query time from the ctxvalues array.

Why use them​

  • Safety — no string concatenation, no injection risk.
  • Reuse — the same query string with different inputs.
  • Caching — the parser can cache the parsed plan keyed by the literal query.

Example​

Query:

mydb.users[email = $1]

Request:

{
  "query": "mydb.users[email = $1]",
  "ctxvalues": ["ada@example.com"]
}

Multiple parameters​

mydb.orders[user_id = $1 and status = $2]
{ "ctxvalues": ["42", "paid"] }

Order matters: $1 is the first array element, $2 is the second.

With context rules​

Context rules in the protocol use the same $N placeholders, but they pull from ctxvalues of the incoming request, not from the query string. So:

Protocol:

"orders": { "context": { "account": "mydb.orders[user_id = $1]" } }

Request:

{ "query": "mydb.orders{id, total}", "ctxkey": "account", "ctxvalues": ["42"] }

ONQL combines these into:

mydb.orders[user_id = "42"]{id, total}