As Magento introduces patches instead of upgrade data and upgrade schema. In earlier version of Magento upgrade data and upgrade schema works by versioning but in Magento 2.3 it only executed the one patch files only one time. So how should Magento knows that this patch file is already executed??
Magento stores the list of all the patches that has already been applied in the database table
An unapplied patch will be applied on running the
For Magento 2:
From the magento root directory run below
php bin/magento indexer:reindex