20. Magento Austria meetup - EAV Principles
- 1. Mohammad Haj-Salem Magento database Principles of the EAV system and implementation in Magento!
- 2. Who is Mohammad Haj-Salem? ❏ Software engineer graduated from Damascus university in 2010 ❏ Web developer ❏ Oracle solutions consultant ❏ ODI/ EDQ data integration - data quality Specialist ❏ ETL/ELT processes driven by SOA(Service-oriented architecture) ❏ PL/SQL processes ❏ Database designer ❏ Technical analyst ❏ Magento Developer for almost one and half a year in E-CONOMIX. (Nov. 2015) Experiences
- 3. Brainstorming ❏ The first problem an analyst faces is: What attributes do I need for each entity?! ❏ Do I have fixed number of attributes?! ❏ If I was able to include all attributes, will all of them have values or I'll get a mega null values table?! ❏ Is it applicable to have all needed attributes in e-commerce area ?!
- 4. Database modelling A database model shows the logical structure of a database, including the relationships and constraints that determine how data can be stored and accessed. Some types of database models ❏ Hierarchical database model ❏ Relational model // most common model ❏ Network model ❏ Object-oriented database model ❏ Entity-relationship model ❏ Document model ❏ EAV model ❏ Star schema ❏ NoSQL database models
- 5. Magento uses EAV What’s EAV? EAV source:http://devdocs.magento.com/
- 6. What is EAV Wikipedia defines EAV as Entity-Attribute-Value model (EAV), also known as object-attribute-value model and open schema is a data model that is used in circumstances where the number of attributes (properties, parameters) that can be used to describe a thing (an "entity" or "object") is potentially very vast, but the number that will actually apply to a given entity is relatively modest. In mathematics, this model is known as a sparse matrix. source:http://devdocs.magento.com/
- 7. Facts Source: Magento CE 1.9.2.2 database diagram ❏ Magento CE 1.9.2.2 initial installation has 333 tables! ❏ 19 tables start with core_* ❏ 47 tables start with sales_* ❏ 84 tables start with catalog_*
- 8. M2 Facts ❏ Magento CE 2.1.3 initial installation has 315 tables ❏ 1 table starts with core_* ❏ 38 tables start with sales_* ❏ 76 tables start with catalog_* Source: Magento CE 2.1.3 database diagram
- 9. Why Magento uses EAV Magento uses EAV database model for easy upgrade and development as this model gives more flexibility to play with data and attributes. ❏ No alter tables scripts needed ❏ No broken ORM after upgrade ❏ EAV gives developers more control over attributes, data and how to group them
- 10. EAV vs Row modelling ❏ Sparseness of attributes ❏ In EAV model one row describes one attribute on the other hand the row modelling one row describes one entity ❏ In row model new attribute means new column “(DDL) Data Definition Language” , in EAV new attribute is new row “(DML) Data Manipulation Language” Products product_id prod_name price new_attribute Product_id prod_name price new_attribute …. 1 Prod1 10 nA1 2 Prod2 20 nA2
- 11. EAV vs Row modelling attribute_id = attribute_id attributes attribute_id name data_type 1 prod_name varchar 2 price decimal entity entity_id column_1 1 column_value 2 c_v_2 attribute_values_varchar value_id attribute_id entity_id value 1 1 1 prod1 2 1 2 prod2 entity_id = entity_id attribute_values_decimal value_id attribute_id entity_id value 1 2 1 10 2 2 2 20
- 12. EAV vs Row modelling ❏ Performance wise ❏ row modelling is faster as far as a query runs on one table ❏ EAV modelling can be SQL intensive, this why you have to be accurate adding attributes to select in Magento (we’re going to talk about this part later on.)
- 13. Magento uses the EAV model
- 14. Magento uses the EAV model ❏ eav_attribute table contains all attributes ❏ The name of the attribute is saved as attribute_code ❏ entity_type_id a foreign key from the table eav_entity_type attribute_id smallint entity_type_id smallint attribute_code varchar .. ..
- 15. Magento uses the EAV model ❏ eav_entity_type table contains all entity types in Magento entity_type_id smallint entity_type_code varchar(50) entity_model varchar(255) .. ..
- 16. Magento uses the EAV model Is he going to go through all those tables?! Nope!
- 17. But, it worth mentioning {entity_type_code}_entity {entity_type_code}_entity_{dataType}
- 18. How to create EAV Model in Magento
- 19. How to create EAV Model in Magento ❏ Define a model in config.xml <global> <!-- ... --> <models> <!-- ... --> <complexworld> <class>Alanstormdotcom_Complexworld_Model</class> <resourceModel>complexworld_resource_eav_mysql4</resourceModel> <resourceModel>complexworld_resource_eav_resource</resourceModel> </complexworld> <!-- ... --> </models> <!-- ... --> </global> ❏ Notice the <resourceModel/> node ❏ EAV: {model}_resource_eav_mysql4 ❏ Normal: {model}_mysql4 was deprecated after 1.6.x.x ❏ Notice: {model}_mysql4 =>{model}_resource source:http://alanstorm.com/magento_advanced_orm_entity_attribute_value_part_1/
- 20. How to create EAV model in Magento - usual steps ❏ inform Magento about your resource <models> <!-- ... --> <complexworld_resource_eav_mysql4> <class>Alanstormdotcom_Complexworld_Model_Resource_Eav_Mysql4</class> <class>Alanstormdotcom_Complexworld_Model_Resource_Eav_Resource</class> <entities> <eavblogpost> <table>eavblog_posts</table> </eavblogpost> </entities> </complexworld_resource_eav_mysql4> <!-- ... --> </models> source:http://alanstorm.com/magento_advanced_orm_entity_attribute_value_part_1/
- 21. How to create EAV Model in Magento - Create your classes ❏ Model class class Alanstormdotcom_Complexworld_Model_Eavblogpost extends Mage_Core_Model_Abstract { protected function _construct() { $this->_init('complexworld/eavblogpost'); } } ❏ Model’s resource classes class Alanstormdotcom_Complexworld_Model_Resource_Eav_Mysql4_Eavblogpost extends Mage_Eav_Model_Entity_Abstract { public function _construct() { $resource = Mage::getSingleton('core/resource'); $this->setType('complexworld_eavblogpost'); //entity_type_code $this->setConnection( $resource->getConnection('complexworld_read'), $resource->getConnection('complexworld_write') ); } } EAV:Mage_Eav_Model_Entity_Abstract Normal: Mage_Core_Model_Resource_Db_Abstract (+) source:http://alanstorm.com/magento_advanced_orm_entity_attribute_value_part_1/
- 22. How to create EAV Model in Magento - setup script In order to make our Module working we need to insert Row in eav_entity_type, eav_attribute_group and eav_attribute_set, which can be manual or Automated source:http://alanstorm.com/magento_advanced_orm_entity_attribute_value_part_1/
- 23. How to create EAV model in Magento - setup script ❏ Create setup script <resources> <!-- ... --> <complexworld_setup> <setup> <module>Alanstormdotcom_Complexworld</module> <class>Alanstormdotcom_Complexworld_Entity_Setup</class> </setup> <connection> <use>core_setup</use> </connection> </complexworld_setup> <!-- ... --> </resources> ❏ setup classes will be extending Mage_Eav_Model_Entity_Setup rather than Mage_Core_Model_Resource_Setup class Alanstormdotcom_Complexworld_Entity_Setup extends Mage_Eav_Model_Entity_Setup { source:http://alanstorm.com/magento_advanced_orm_entity_attribute_value_part_1/
- 24. How to create EAV Model in Magento - Configure new Entity ❏ In the setup class public function getDefaultEntities() { return array ( 'complexworld_eavblogpost' => array( 'entity_model' => 'complexworld/eavblogpost', 'attribute_model' => '', 'table' => 'complexworld/eavblogpost', 'attributes' => array( 'title' => array( 'type' => 'varchar', 'backend' => '', 'frontend' => '', 'label' => 'Title', 'input' => 'text', 'class' => '', 'source' => '', 'global' => 0, 'visible' => true, 'required' => true, 'user_defined' => true, 'default' => '', 'searchable' => false, 'filterable' => false, 'comparable' => false, 'visible_on_front' => false, 'unique' => false, ), ), ) ); } source:http://alanstorm.com/magento_advanced_orm_entity_attribute_value_part_1/ After running the script we’ll get new row in eav_attribute and eav_entity_attribute
- 25. How to create EAV model in Magento - Data set/get ❏ Set a value $weblog2 = Mage::getModel('complexworld/eavblogpost'); $weblog2->set{AttributeCode}(‘value’); $weblog2->setTitle(‘value’); $weblog2->save(); ❏ Get a value $weblog2 = Mage::getModel('complexworld/eavblogpost'); $entries = $weblog2->getCollection() ->addAttributeToSelect('{AttributeCode}'); $entries = $weblog2->getCollection() ->addAttributeToSelect('title'); Take care by using $weblog2->getCollection()->addAttributeToSelect(*); source:http://alanstorm.com/magento_advanced_orm_entity_attribute_value_part_1/
- 26. Really flexible Even though it sometimes causes headache ❏ Performance ❏ Changes in datatype ❏ Manual imports ❏ 3rd Party User Complexity