Autonomous Database supports private access from Oracle Cloud Infrastructure resources in a VCN through a service gateway.
A service gateway allows connectivity to Autonomous Database from private IP addresses in private subnets without requiring a NAT Gateway in your VCN. After a service gateway is configured, there are no special steps required to connect to Autonomous Database. Use the same connection steps as described in this chapter, depending on your application type or the client tool you are using to connect to the database.
After a service gateway is configured, there are no special steps required to access Oracle Application Express or Database Actions, or to consume RESTful services published in Oracle REST Data Services.
See Access to Oracle Services: Service Gateway for details.