How are product attributes and attribute options stored in Magento database?

Question

I am trying to figure out how the linkage between attribute and attribute options, and product and attributes are made in Magento. Is there any reference to how this is work

Answer 1

I've found these queries to be very helpful for hunting down things like - where does it say the product color is black?, for example.

-- show_product_attr.sql
select
   p.entity_id,
   p.entity_type_id,
   p.attribute_set_id,
   p.type_id,
   p.sku,
   a.attribute_id,
   a.frontend_label as attribute,
   av.value
from
   catalog_product_entity p
   left join catalog_product_entity_{datatype} av on
      p.entity_id = av.entity_id
   left join eav_attribute a on
      av.attribute_id = a.attribute_id
where
   -- p.entity_id = 28683
   -- p.sku = '0452MR'
   p.entity_id = {eid}
;

And for attr_options

-- show_product_attr_options.sql
select
   p.entity_id,
   -- p.entity_type_id,
   -- p.attribute_set_id,
   p.type_id,
   p.sku,
   a.attribute_id,
   a.frontend_label as attribute,
   -- a.attribute_code,
   av.value,
   ao.*
from
   catalog_product_entity p

   left join catalog_product_entity_int av on
      p.entity_id = av.entity_id

   left join eav_attribute a on
      av.attribute_id = a.attribute_id
   left join eav_attribute_option_value ao on
      av.value = ao.option_id 
where
   -- p.entity_id = 28683
   p.entity_id = {eid}
;

You need to replace {datatype} with text, varchar, int, decimal, etc, for the first query, and {eid} with entity_id for both queries. Which you can do on the command like like this:

$ cat show_product_attr_options.sql | sed -e "s/{eid}/30445/" | mysql -uUSER -pPASS DATABASE -t
+-----------+---------+--------------+--------------+---------------------------+-------+----------+-----------+----------+--------------------+-------------+
| entity_id | type_id | sku          | attribute_id | attribute                 | value | value_id | option_id | store_id | value              | colorswatch |
+-----------+---------+--------------+--------------+---------------------------+-------+----------+-----------+----------+--------------------+-------------+
|     30445 | simple  | 840001179127 |           96 | Status                    |     1 |     5972 |         1 |        0 | Male               | NULL        |
|     30445 | simple  | 840001179127 |          102 | Visibility                |     1 |     5972 |         1 |        0 | Male               | NULL        |
|     30445 | simple  | 840001179127 |          122 | Tax Class                 |     2 |     5973 |         2 |        0 | Female             | NULL        |
|     30445 | simple  | 840001179127 |          217 | Size                      |   257 |    17655 |       257 |        0 | XS                 | NULL        |
|     30445 | simple  | 840001179127 |          217 | Size                      |   257 |    17657 |       257 |        1 | XS                 | NULL        |
|     30445 | simple  | 840001179127 |          224 | Color                     |   609 |    18717 |       609 |        0 | Arctic Ice Heather | NULL        |
|     30445 | simple  | 840001179127 |          260 | Featured                  |     0 |     NULL |      NULL |     NULL | NULL               | NULL        |
|     30445 | simple  | 840001179127 |          262 | Clearance Product         |     0 |     NULL |      NULL |     NULL | NULL               | NULL        |
|     30445 | simple  | 840001179127 |          263 | Skip from Being Submitted |     0 |     NULL |      NULL |     NULL | NULL               | NULL        |
|     30445 | simple  | 840001179127 |          283 | Discontinued              |     0 |     NULL |      NULL |     NULL | NULL               | NULL        |
+-----------+---------+--------------+--------------+---------------------------+-------+----------+-----------+----------+--------------------+-------------+

A similar set of sql scripts can be created for catalog.

Answer 2

As Alan Storm says: "you do not have to know about how your db works. You have to learn how the models work ". (This is not an exact quote. I gave you the meaning).

But I created own scheme to understand the DB structure. So this screen shows how it works:

Hope, it helps.

Also I recommend you to look through these links:

http://www.magentocommerce.com/wiki/2_-_magento_concepts_and_architecture/magento_database_diagram

http://alanstorm.com/magento_advanced_orm_entity_attribute_value_part_1

Answer 3

1) The attributes are stored in eav_attribute. There you get the attribute_id.

2) The options are stored in eav_attribute_option_value. There yout get the option_id.

3) The options are assigned to the product in catalog_product_entity_varchar. There you need the entity_id of the product, the attribute_id from 1) and the value which are the comma separated option_ids from 2)

Answer 4

SELECT pei.value 
FROM `catalog_product_entity_int` pei 
JOIN `eav_attribute` ea 
ON pei.attribute_id = ea .attribute_id 
WHERE pei.entity_id = {your product_id} 
AND ea.attribute_code = '{your attribute_code}'

Note that there are a number of different tables like catalog_product_entity_int depending on the type of the attribute, so one of those other ones could be appropriate.

Answer 5

Product Attributes are extra values that you can assign to a product and is stored in the main EAV table, by name, and the data is then stored in a few different tables based on the data type, like varchar, decimal, text Integer, date, etc.

if you had multiple values for your Product Attribute, then that will be stored in the Attribute Options tables, again, different tables based on the data type.

the following link explains the relationships better: http://www.magentocommerce.com/wiki/2_-_magento_concepts_and_architecture/magento_database_diagram

And deeper developer's detail: http://www.magentocommerce.com/knowledge-base/entry/magento-for-dev-part-7-advanced-orm-entity-attribute-value

And Attribute sets will be the other thing you come across, like the name suggests, a set of attributes grouped together. http://www.magentocommerce.com/knowledge-base/entry/how-do-i-create-an-attribute-set

HTH Shaun