当您添加新的嵌套级别时，使用文字字符串将变得可读性较差：

CREATE TYPE pencil_count AS(pencil_color varchar(30)
       ,"count" int);

CREATE TYPE pencil_count_with_date AS(date_ date
                                     ,pencil_count pencil_count[]);

CREATE TABLE pencils(id serial, pencils_ pencil_count_with_date[]);

INSERT INTO pencils(pencils_) 
VALUES('{"(
               \"2016-03-13\",
               \"{
                   \"\"(Blue,5)\"\",
                   \"\"(Red,2)\"\"
               }\"
          )"}');   

SELECT pencils_[1].pencil_count[1].pencil_color
FROM pencils;

字符串

SqlFiddleDemo

备注：
1.你需要引用每个级别，"根据嵌套级别被\转义。
1.这种模式看起来像是试图将OO世界引入数据库。它可能比规范化版本更难维护，也更慢。Related question.
1.如果需要的话，你可以用$$来引用字符串。
1.使用ARRAY和ROW可以更容易地发现每个级别的开始和停止位置。

再次，问Postgres.扩展的过程为your previous question：

CREATE TEMP TABLE pencil_count (
  pencil_color varchar(30)
, count integer
);

CREATE TABLE pencil_count_with_date (
  date_ date
, pencil_count pencil_count[]
);

CREATE TABLE pencils (
  id serial
, pencils_ pencil_count_with_date[]
);

字符串
询问Postgres每个嵌套级别：

INSERT INTO pencil_count VALUES ('red' , 1), ('blue', 2);

SELECT ARRAY(SELECT p FROM pencil_count p)::text AS p_row_arr;

-- with result from above:
INSERT INTO pencil_count_with_date(date_, pencil_count)
VALUES ('2016-04-14', '{"(red,1)","(blue,2)"}')
     , ('2016-04-14', '{"(red,3)","(blue,4)"}');

SELECT ARRAY(SELECT p FROM pencil_count_with_date p)::text AS p2_row_arr;

-- with result from above:
INSERT INTO pencils(pencils_)
VALUES
  ('{"(2016-04-14,\"{\"\"(red,1)\"\",\"\"(blue,2)\"\"}\")"
    ,"(2016-04-15,\"{\"\"(red,3)\"\",\"\"(blue,4)\"\"}\")"}');

SELECT id, pencils_::text FROM pencils;

型
测试结果：

id | pencils_
---+-------------------------------------------------------
1  | {"(2016-04-14,\"{\"\"(red,1)\"\",\"\"(blue,2)\"\"}\")"
     ,"(2016-04-15,\"{\"\"(red,3)\"\",\"\"(blue,4)\"\"}\")"}

型
fiddle的
老小提琴
到目前为止，我完全同意这个建议：多层嵌套行类型通常是复杂和低效的。
更多关于你上一个问题的回答：

• 复合类型数组的正确语法