public static String getQualified(String catName, String dbName) {
    return catName + CAT_DB_TABLE_SEPARATOR + dbName;
  }
Build a DatabaseName from a string of the form [catalog.]database.
@param name name, can be "db" or "cat.db"
@param defaultCatalog default catalog to use if catalog name is not in the name.  This can
                      be null if you are absolutely certain that the catalog name is
                      embedded in name.  If you want the default catalog to be determined by
                      the session, use SessionState.getCurrentCatalog().  If you want it to
                      be determined by the default for the Hive instance or you are not in a
                      session, use MetaStoreUtils.getDefaultCatalog().
@return new DatabaseName object.
storage-api/src/java/org/apache/hadoop/hive/common/DatabaseName.java