Add Column with random value Sequelize PostgreSQL - node.js

Question

I want to add column with NOT_NULL constraint so column will contain random default values following is my code how can i do this
up: function (queryInterface, Sequelize, done) {
queryInterface.addColumn(
{
tableName: 'someTable',
schema: 'sometemplate'
},
'someColumn', //column name
{ //column date type and constraint
type: Sequelize.STRING,
allowNull: false,
defaultValue: // I want this to random value
})
.then(function () { done() })
.catch(done);
}

Answer 1

PostgreSQL example:
CREATE OR REPLACE FUNCTION f_random_text(
length integer
)
RETURNS text AS
$body$
WITH chars AS (
SELECT unnest(string_to_array('A B C D E F G H I J K L M N O P Q R S T U V W X Y Z 0 1 2 3 4 5 6 7 8 9', ' ')) AS _char
),
charlist AS
(
SELECT _char FROM chars ORDER BY random() LIMIT $1
)
SELECT string_agg(_char, '')
FROM charlist
;
$body$
LANGUAGE sql;
DROP TABLE IF EXISTS tmp_test;
CREATE TEMPORARY TABLE tmp_test (
id serial,
data text default f_random_text(12)
);
INSERT INTO tmp_test
VALUES
(DEFAULT, DEFAULT),
(DEFAULT, DEFAULT)
;
SELECT * FROM tmp_test;
id | data
----+--------------
1 | RYMUJH4E0NIQ
2 | 7U4029BOKAEJ
(2 rows)
Apparently you can do this. (Of course, you can add other characters as well, or use other random string generator as well - like this, for example.)
ref: https://dba.stackexchange.com/questions/19632/how-to-create-column-in-db-with-default-value-random-string