mapped_pages:
DESCRIBE | DESC
    [CATALOG identifier]? <1>
    [INCLUDE FROZEN]?     <2>
    [table_identifier |   <3>
     LIKE pattern]        <4>
*).Description: DESC and DESCRIBE are aliases to SHOW COLUMNS.
DESCRIBE emp;
       column       |     type      |    mapping
--------------------+---------------+---------------
birth_date          |TIMESTAMP      |datetime
dep                 |STRUCT         |nested
dep.dep_id          |VARCHAR        |keyword
dep.dep_name        |VARCHAR        |text
dep.dep_name.keyword|VARCHAR        |keyword
dep.from_date       |TIMESTAMP      |datetime
dep.to_date         |TIMESTAMP      |datetime
emp_no              |INTEGER        |integer
first_name          |VARCHAR        |text
first_name.keyword  |VARCHAR        |keyword
gender              |VARCHAR        |keyword
hire_date           |TIMESTAMP      |datetime
languages           |TINYINT        |byte
last_name           |VARCHAR        |text
last_name.keyword   |VARCHAR        |keyword
name                |VARCHAR        |keyword
salary              |INTEGER        |integer