CODEWITHSUNDEEP
oracle-databaseoracle11g
Caffeinated
Caffeinated

Reputation: 12484

In Oracle database, what is the $ - notation?

SELECT (space_limit/1024/1024) "Max Size (MB)",
       (space_used/1024/1024)  "Current Size (MB)"
 FROM v$recovery_file_dest;

Here you have v$recovery_file_dest, what does the $ mean here? I see v$ a lot, and was wondering if it means anything specifically.

Upvotes: 1

Views: 73

Answers (1)

Alex Poole
Alex Poole

Reputation: 191285

As others have mentioned in comments, it doesn't mean anything per se; as the 7th point in the database naming rules; $ is indeed just another valid character.

The concepts guide has a section on dynamic performance views, which says:

SYS owns the dynamic performance tables, whose names begin with V_$. Views are created on these tables, and then public synonyms prefixed with V$. For example, the V$DATAFILE view contains information about data files. The V$FIXED_TABLE view contains information about all of the dynamic performance tables and views.

So it's just their naming convention for these views. You can get a list of those views, and that they do/tell you, from the database reference guide.

There's nothing stopping you, but it would probably be a good idea to avoid naming your own objects using the same convention, though I don't think you had any intention of doing so...

Upvotes: 4

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