oracle - "audit create session by session" vs. "audit create session by access"? -

when enabling auditing create session following way:

audit create session session; 

then querying following:

select * dba_priv_audit_opts; 

the result is:

username | proxy_name | audit_option   | success   | failure  | ...............................................................  -       | -          | create session | access | access| 

but, when enabling auditing create session following way:

 audit create session access; 

then querying following:

select * dba_priv_audit_opts; 

the result same:

username | proxy_name | audit_option   | success   | failure  | ...............................................................  -       | -          | create session | access | access| 

why? have idea?

11gr2 , above:

by session disabled , auditing done per access.

11gr1 , below:

the difference between by session , by access when specify by session oracle try merge multiple audit entries 1 record when session , action audited match.

it works sql statements other ddl though, above link:

if specify statement options or system privileges audit data definition language (ddl) statements, database automatically audits access regardless of whether specify session clause or access clause.

since create session ddl statement oracle audits statement access.