code: public int getInternalId(String id) {
  		DatabaseEntry key = new DatabaseEntry();
  		StringBinding.stringToEntry(id, key);
  		DatabaseEntry data = new DatabaseEntry();
  		// check if the id already exists in id to iid database
  		if ((idToIidDB.get(null, key, data, null) == OperationStatus.SUCCESS)) {
  			return IntegerBinding.entryToInt(data);
  		} else {
  			return -1;
  		}
  	}
docs: Returns the internal id assigned to the vector with the given id or -1 if the id is not found. Accesses
  the BDB store!
  
  @param id
  The id of the vector
  @return The internal id assigned to this vector or -1 if the id is not found.