What is Active Record(AR) in yii ?

Active Record provides an object-oriented interface for accessing and manipulating data stored in databases. An Active Record class is associated with a database table, an Active Record instance corresponds to a row of that table, and an attribute of an Active Record instance represents the value of a particular column in that row. Instead of writing raw SQL statements, you would access Active Record attributes and call Active Record methods to access and manipulate the data stored in database tables. Read more from http://www.yiiframework.com/doc-2.0/guide-db-active-record.html