Unique Key column in the database table used to avoid the duplication of data in the same column.
Using a unique column key, Table gives guarantees to unique value for the column from the set of records in a table.
Drop or remove Table from Database using DataPatchInterface Magento 2.
Drop or Remove a database Table in Magento 2 using the Setup folder DataPatchInterface approach.
From Magento 2.3 New Concept Setup Patch Data was introduced.
Plugin for Subscribe() method of email subscription Magento 2.
Subscribe by Email id in Magento 2 Use Subscribe($email) method to newsletter subscription in native code.
Native Class:
Magento\Newsletter\Model\Subscriber (Magento_Newsletter)