{"id":16293,"date":"2018-07-17T14:33:26","date_gmt":"2018-07-17T12:33:26","guid":{"rendered":"https:\/\/belvg.com\/blog\/?p=16293"},"modified":"2021-02-18T14:03:12","modified_gmt":"2021-02-18T12:03:12","slug":"how-eav-data-storage-works-in-magento-2-part-2","status":"publish","type":"post","link":"https:\/\/belvg.com\/blog\/how-eav-data-storage-works-in-magento-2-part-2.html","title":{"rendered":"How EAV Data Storage Works in Magento 2: Part 2"},"content":{"rendered":"\n

There is not much difference for a developer in EAV and Flat collections. The creation of models, resource models and collections is very similar. Let’s describe the key differences between EAV and flat table collections and consider creating classes for EAV (City) and Flat (Country). This is Part 2 of the EAV data storage review, check out Part 1<\/a> to catch up on the topic.<\/p>\n

Collections<\/a>
\nResource models<\/a>
\nModels<\/a>
\nThe differences between EAV and FLAT classes<\/a>
\nWhen to use EAV for a new entity<\/a>
\nThe pros and cons of EAV architecture<\/a><\/p>\n

<\/a>Collections<\/span><\/strong><\/h2>\n

EAV<\/span><\/p>\n

<?php\r\nnamespace Belvg\\Geo\\Model\\ResourceModel\\City;\r\nclass Collection extends \\Magento\\Eav\\Model\\Entity\\Collection\\AbstractCollection\r\n{\r\n   protected function _construct()\r\n   {\r\n       $this->_init(\r\n           'Belvg\\Geo\\Model\\City',\r\n           'Belvg\\Geo\\Model\\ResourceModel\\City'\r\n       );\r\n   }\r\n}<\/pre>\n
Flat<\/span><\/h4>\n
<?php\r\nnamespace Belvg\\Geo\\Model\\ResourceModel\\Country;\r\nclass Collection extends \\Magento\\Framework\\Model\\ResourceModel\\Db\\Collection\\AbstractCollection\r\n{\r\n   protected function _construct()\r\n   {\r\n       $this->_init(\r\n           'Belvg\\Geo\\Model\\Country',\r\n           'Belvg\\Geo\\Model\\ResourceModel\\Country'\r\n       );\r\n   }\r\n}<\/pre>\n
<\/a>
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<\/a>Resource models<\/span><\/strong><\/h2>\n
EAV<\/span><\/p>\n
<?php\r\nnamespace Belvg\\Geo\\Model\\ResourceModel;\r\nclass City extends \\Magento\\Eav\\Model\\Entity\\AbstractEntity\r\n{\r\n   public function getEntityType()\r\n   {\r\n       if (empty($this->_type)) {\r\n           $this->setType(\\Belvg\\Geo\\Model\\City::ENTITY);\r\n       }\r\n       return parent::getEntityType();\r\n   }\r\n}<\/pre>\n
Flat<\/span><\/p>\n
<?php\r\nnamespace Belvg\\Geo\\Model\\ResourceModel;\r\nclass Country extends \\Magento\\Framework\\Model\\ResourceModel\\Db\\AbstractDb\r\n{\r\n   protected function _construct()\r\n   {\r\n       $this->_init(\r\n           'belvg_geo_country',\r\n           'entity_id'\r\n       );\r\n   }\r\n}<\/pre>\n
<\/a>Models<\/span><\/strong><\/h2>\n
EAV<\/span><\/p>\n
<?php\r\nnamespace Belvg\\Geo\\Model;\r\nclass City extends \\Magento\\Framework\\Model\\AbstractModel\r\n{\r\n   const ENTITY = 'belvg_geo_city';\r\n\r\n   protected function _construct()\r\n   {\r\n       $this->_init('Belvg\\Geo\\Model\\ResourceModel\\City');\r\n   }\r\n}<\/pre>\n
Flat<\/span><\/p>\n
<?php\r\nnamespace Belvg\\Geo\\Model;\r\nclass Country extends \\Magento\\Framework\\Model\\AbstractModel\r\n{\r\n   protected function _construct()\r\n   {\r\n       $this->_init('Belvg\\Geo\\Model\\ResourceModel\\Country');\r\n   }\r\n}<\/pre>\n
<\/a>The differences between EAV and FLAT classes<\/strong><\/span><\/h2>\n
Additionally, methods that take an attribute parameter as its code or its object have been added in the EAV collection:<\/p>\n