private static Function getFunction(String procedureCatalog, String catalog,
String procedureName) {
Function function = functions.get(getKey(procedureCatalog, catalog, procedureName));
if (function!=null) return function;
function = new FunctionDDLUtils();
if (procedureCatalog!=null)
function.setCatalog(procedureCatalog);
else
function.setCatalog(catalog);
function.setName(procedureName);