I have site up enterprise database based on oracle and run successfully with arcgis server 10.3.1 ,but i wan't to create a enterprise database base on PostgreSQL now, how to delete the enterprise database and based on oracle with the sde connection?
There is no way to delete the Oracle database via ArcCatalog or any other esri tools. The database connection in ArcCatalog is merely an SDE connection file that is stored on the machine making the connection to the server machine. In order to delete the database you will need to use Oracle tools to do so. You can achieve this by running Database Configuration Assistant (DBCA) or by using the DROP DATABASE statement in an Oracle developer program (SQL Plus, SQL Developer, TOAD, etc.).