Question

From a book, I have read

Whenever you perform a SQL statement, the Oracle opens an area of
memory in which the command is parsed and executed. This area is
called a cursor.

It applies both to explicit and implicit cursors. But I’m curious about another thing – can a cursor be considered as a intermediate place (in memory) where Oracle returns final record set and uses it as a source for fetching records?

Answer 1

A cursor is a pointer to that intermediate set of data returned from the query. It contains state information for producing and accessing the result. From the Concepts Doc:

A cursor is a name or handle to a specific private SQL area. As shown
in Figure 14-5, you can think of a cursor as a pointer on the client
side and as a state on the server side.

The result of a query is a result set and is pointed to by the cursor. It is stored in a temporary location, either in memory or on disk. From the concepts doc:

A temporary tablespace contains schema objects only for the duration
of a session. Locally managed temporary tablespaces have temporary
files (temp files), which are special files designed to store data in
hash, sort, and other operations. Temp files also store result set
data when insufficient space exists in memory.