stringer.key(Members.OUTPUT_COLUMNS.name());
stringer.array();
for (int col = 0; col < m_outputColumns.size(); col++) {
PlanColumn column = m_context.get(m_outputColumns.get(col));
column.toJSONString(stringer);
}
stringer.endArray();
}
abstract protected void loadFromJSONObject(JSONObject obj, Database db) throws JSONException;