Before you can begin developing an application, you must ensure that the development system you are using has network access to the database you want to connect to.

The network visibility of an Autonomous Database is determined by the networking configuration of the dedicated infrastructure hosting it.

This networking configuration, which is designed and implemented by the infrastructure's Fleet Administrator and your Oracle Cloud tenancy's network administrator, can range from very open access to very restricted access, depending on the security needs of the databases that are to be created on the infrastructure. To learn more about this networking configuration, see Plan Access Controls and Create Supporting Resources.

Here are the two commonest networking configurations, together with instructions for configuring a development system to have network access to a database created in the configuration.

• Private Oracle Cloud network. Databases do not have public IP addresses and are not network-visible to the public internet.

  In this case, you need to create an Oracle Cloud Compute instance and install software on it to make it a development system that meets your needs. Depending on the specifics of the network configuration, you may create this instance in the same VCN (virtual cloud network) and subnet as the database, or in the same VCN but a different subnet, or in a different VCN and subnet that have been network-peered to the database's VCN.

  To simplify creating such an instance, Oracle provides a Marketplace image that already contains many development tools and utilities. For instructions on using this image to create a development system, see Compute VM as a Development System.

• Private Oracle Cloud network with a gateway to a VPN. Databases do not have public IP addresses and are not network-visible to the public internet; however, the private cloud network in which they reside has a gateway to a VPN.

  In this case, your existing development system has network access to a database after it is connected to the VPN.

Here are two less common networking configurations, together with instructions for configuring a development system to have network access to a database created in the configuration.

• Public internet with a gateway. Databases are network-visible to a specific list of IP addresses on the public internet.

  In this case, you need get the public IP address of your existing development system added to the internet gateway that limits public access. The DBA who created the database you want to connect to should be able to provide you instructions to do this.

• Public internet. Databases are network-visible to the public internet.

  In this case, your existing development system has network access to databases, provided that your system has internet access .

• Compute VM as a Development System