docs: public void init(PMContext context) throws Exception {
          // init default values
          if (getDriver() == null) {
              setDriver(DERBY_EMBEDDED_DRIVER);
          }
          if (getDatabaseType() == null) {
              setDatabaseType("derby");
          }
          if (getUrl() == null) {
              setUrl("jdbc:derby:" + context.getHomeDir().getPath() + "/db/itemState;create=true");
          }
          if (getSchemaObjectPrefix() == null) {
              setSchemaObjectPrefix("");
          }
          super.init(context);
          // set properties       
          if (DERBY_EMBEDDED_DRIVER.equals(getDriver())) {
              conHelper.exec("CALL SYSCS_UTIL.SYSCS_SET_DATABASE_PROPERTY "
                      + "('derby.storage.initialPages', '" + derbyStorageInitialPages + "')");
              conHelper.exec("CALL SYSCS_UTIL.SYSCS_SET_DATABASE_PROPERTY "
                      + "('derby.storage.minimumRecordSize', '" + derbyStorageMinimumRecordSize + "')");
              conHelper.exec("CALL SYSCS_UTIL.SYSCS_SET_DATABASE_PROPERTY "
                      + "('derby.storage.pageCacheSize', '" + derbyStoragePageCacheSize + "')");
              conHelper.exec("CALL SYSCS_UTIL.SYSCS_SET_DATABASE_PROPERTY "
                      + "('derby.storage.pageReservedSpace', '" + derbyStoragePageReservedSpace + "')");
              conHelper.exec("CALL SYSCS_UTIL.SYSCS_SET_DATABASE_PROPERTY " + "('derby.storage.pageSize', '"
                      + derbyStoragePageSize + "')");
          }
      }