I'm learning about Collections, Repositories and DTO, and I'm still trying to figure out what's the best way to query a table to fetch data. I also found that we can use \Magento\Framework\App\ResourceConnection for direct SQL queries.
My question is:
Which way should I use for future projects, since my goal is to use table data to create APIs and also frontend pages? Is there a better way for each case?
You can use this for test, using ObjectManager like this is not recommanded.
$objectManager = \Magento\Framework\App\ObjectManager::getInstance(); // Instance of object manager
$resource = $objectManager->get('Magento\Framework\App\ResourceConnection');
$connection = $resource->getConnection();
$tableName = $resource->getTableName('quote'); //gives table name with prefix
//Select Data from table
$sql = "Select X FROM ".$tableName." WHERE Y;
$result = $connection->fetchAll($sql); // gives associated array, table fields as key in array.
But you can use dependency injection to do this properly
