Question

I am trying to avoid anti-pattern in project where I must allow users to create, modify and delete table fields. So I am looking for storing JSON data in table. For example I have table products:

Products
----------------
id,
user_id,
created,
modified,
price,
_custom <-- there will be stored additional columns for each product needs
        {"adjustment":0.13, "weight":14.60, "have_some_individual_label":"value"}

But I can’t see how it is possible to include _column parameters in query. For example, how to query all products where user_id = 1 AND have_some_individual_label = value. Second parameter can be one, ore more (it will be used for filters and analytic). If this is bad approach – what would be better one? Thanks!

Answer 1

If this is bad approach – what would be better one?

The Entity–attribute–value model model:

CREATE TABLE `ProductInfo` (
  `ProductID` BIGINT UNSIGNED NOT NULL,
  `AttributeKey` VARCHAR(20) NOT NULL,
  `AttributeVal` VARCHAR(20),
  PRIMARY KEY (`ProductID`, `AttributeKey`),
  FOREIGN KEY (`ProductID`) REFERENCES `Products` (`id`)
);

INSERT INTO ProductInfo
  (`ProductID`, `AttributeKey`              , `AttributeVal`)
VALUES
  (         1 , 'adjustment'                ,         '0.13'),
  (         1 , 'weight'                    ,        '14.60'),
  (         1 , 'have_some_individual_label',        'value')
;