@Explain(displayName = "if exists", displayOnlyOnTrue = true,
      explainLevels = { Level.USER, Level.DEFAULT, Level.EXTENDED })
  public boolean isIfExists() {
    return ifExists;
  }
DDL task description for DROP VIEW commands.
ql/src/java/org/apache/hadoop/hive/ql/ddl/view/drop/DropViewDesc.java