I am learning Oracle. I am trying to figure out (using the command prompt) the total number of databases that are up.

I tried:

select name from v$database

1 Answer 1


In singletenant (non-CDB, old) architecture: one instance - one database. In multitenant architecture (CDB): one instance - multiple databases.

So first of of you have to know the relationship between instance and database. Then you can identify how many instances do you have on your server (how, it depends on your operating system) and then you have to identify what architecture do you have (non-CDB, CDB).

Than you can make a list of all databases. Take a look at https://stackoverflow.com/questions/36957919/how-to-list-down-the-list-of-pdb-and-cdb-in-oracle-12c

Edit: As mentioned by jmk, you can meet also Oracle RAC.

  • Leaving out RAC where multiple instances form one cluster database. And please be aware that using multiple PDBs is an extra cost option for Enterprise Edition only.
    – jmk
    Commented Feb 24, 2019 at 14:42

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