Key Extraction

[cheqianh]

Sometimes Ion keys are dynamic values that are not known during table creation.

Example:

Example Ion Doc: values "aaaaaaa" and "bbbbbbbb" would be unknown to user at table creation

{
    name: "John Foo",
    documents: {
        "aaaaaaa": {
            type: "drivers_license",
            date_issued: 2007-02-23,
            is_valid: true
        },
        "bbbbbbbb": {
            type: "license_plate",
            state: "Colorado",
            is_valid: true
        }
    }
}

We want Ion-hive-serde to be able to extract fields "aaaaaaa" and "bbbbbbbb" without identifying them.