*/
public void add(QueryVariable variable) throws org.dbwiki.exception.WikiException {
if (_variableIndex.containsKey(variable.name().toUpperCase())) {
throw new WikiQueryException(WikiQueryException.DuplicateVariableDefinition, variable.name() + " already exists");
}
_variableIndex.put(variable.name().toUpperCase(), variable);
_variableListing.add(variable);
}