text: --  @testpoint:opengauss关键字owned(非保留)，自定义数据类型名为explain
  --关键字explain作为数据类型不带引号，创建成功
  drop type if exists owned;
  CREATE TYPE owned AS (f1 int, f2 text);
  select typname from pg_type where typname ='owned';
  drop type owned;
  
  
  --关键字explain作为数据类型加双引号，创建成功
  drop type if exists "owned";
  CREATE TYPE "owned" AS (f1 int, f2 text);
  select typname from pg_type where typname ='owned';
  drop type "owned";
  
  --关键字explain作为数据类型加单引号，合理报错
  drop type if exists 'owned';
  CREATE TYPE 'owned' AS (f1 int, f2 text);
  select * from pg_type where typname ='owned';
  drop type 'owned';
  
  --关键字explain作为数据类型加反引号，合理报错
  drop type if exists `owned`;
  CREATE TYPE `owned` AS (f1 int, f2 text);
  select * from pg_type where typname =`owned`;
  drop type `owned`;