How to query on a field in nested collection of a parent state using VaultCustomQuery

Question

I have a one-to-many relationship where I am trying to add a list of object/class in my state. i.e I have a contract state that has a list of attachments List

Answer 1

Your schema definition is correct (and you can see another example here: Querying nested collections in LinearState states).

However, querying nested collections is not supported by VaultCustomQueryCriteria. You have to do direct JDBC queries to query attributes of the nested collections.

Here is an example of a direct JDBC query in Corda:

@Test
fun `test calling an arbitrary JDBC native query`() {
    val nativeQuery = "SELECT v.transaction_id, v.output_index FROM vault_states v WHERE v.state_status = 0"

    database.transaction {
        val jdbcSession = services.jdbcSession()
        val prepStatement = jdbcSession.prepareStatement(nativeQuery)
        val rs = prepStatement.executeQuery()
        var count = 0
        while (rs.next()) {
            val stateRef = StateRef(SecureHash.parse(rs.getString(1)), rs.getInt(2))
            Assert.assertTrue(cashStates.map { it.ref }.contains(stateRef))
            count++
        }
        Assert.assertEquals(cashStates.count(), count)
    }
}