Chapter 6. SQL Developer Accessibility
SQL Developer has a Connections node for establishing a database session with the target database. The connections may be either newly created or an imported and existing connection that we already had in the previous version of SQL Developer. To create a new database connection, right-click on the Connections node and select New Database Connection. You can also connect to schemas for MySQL, TimesTen, and Hive, as well as some select third-party (non-Oracle) databases, such as Microsoft SQL Server, Sybase Adaptive Server, and IBM DB2, to view metadata and data. However, providing details on such third-party database connections are out of scope of this book. The existing connections are always displayed in the connections pane automatically every time the SQL Developer is started. This list of existing connections is fetched from either tnsnames.ora file
(if it exists); otherwise, the connections information is stored in a connections.xml...