添加列随机值Sequelize PostgreSQL的

Question

我想与NOT_NULL约束添加列，以便列将包含随机默认值下面是我的代码我怎样才能做到这一点

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的例子：

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) 

显然你可以做到这一点。 （当然，您也可以添加其他字符，或者使用其他随机字符串生成器 - 例如，像这样）。 ref：https://dba.stackexchange.com/questions/19632/how-to-create-column-in-db-with-default-value-random-string