public Map<String, String> getForeignKeys() {
    return foreignKeys == null ?
        Collections.emptyMap() :
        jsonSerializer.<Map<String, String>>fromJson(foreignKeys, Map.class);
  }
Get the foreign keys.

@return foreign key map of property name to value
ambari-server/src/main/java/org/apache/ambari/server/orm/entities/ArtifactEntity.java