It is possible to have plugins use their own DB and have things call out to that to retrieve info - e.g. CiviCRM uses it&#x27;s own database to store CRM info (although it&#x27;s also MySQL) and can provide forms for Wordpress pages etc.<p>You can also do some pretty nice data syncing&#x2F;access between the two using Postgres&#x27; Foreign Data Wrappers to access MySQL data within Postgres - unfortunately it doesn&#x27;t look like MySQL has a equivalent for accessing Postgres data from within MySQL.