------------

 один     

(1 запись)

test=> select doublear[1][2] from artest;

 doublear

----------

 a

(1 запись)

test=> update artest set arint[3]=5;

UPDATE 1

test=> select * from artest;

           archar            |  arint  |   doublear   

-----------------------------+---------+---------------

 {"один      ","два       "} | {1,2,5} | {{1,a},{2,b}}

(1 запись)

test=> insert into artest values('{"Q"}', '{123}', '{{}{}}');

INSERT 18961 1

test=> select * from artest;

           archar            |  arint  |   doublear   

-----------------------------+---------+---------------

 {"один      ","два       "} | {1,2,5} | {{1,a},{2,b}}