public static boolean isExternal(Map<String, String> tableParams){
    return isPropertyTrue(tableParams, "EXTERNAL");
  }
Determines whether an table needs to be purged or not.

@param table table of interest

@return true if external table needs to be purged
standalone-metastore/metastore-common/src/main/java/org/apache/hadoop/hive/metastore/utils/MetaStoreUtils.java