CREATE CONTEXT
create context context-namespace using package-name;
create context context-namespace using package-name initialized externally;
create context context-namespace using package-name initialized globally;
create context context-namespace using package-name accessed globally;
create context creates a context namespace.
Such a context namespace is a container, if you will, for attribute value pairs.
A value for an attribute is set by calling
dbms_session.set_context('context-namespace', 'attribute-value', value).
For security reasons, Oracle only allows to execute dbms_session.set_context from within the package that was associated in the create context statement.
The value of an attribute can the be queried with
sys_context('context-namespace', 'attribute-name').
Example
conn / as sysdba
create user rene
identified by rene
default tablespace users
temporary tablespace temp;
grant create session,
create procedure,
create any context
to rene;
conn rene/rene
create context some_context using some_package;
create package some_package as
procedure set_value_in_context(some_value in varchar2);
end some_package;
/
create package body some_package as
procedure set_value_in_context(some_value in varchar2) is
begin
dbms_session.set_context('some_context', 'some_attribute', some_value);
end set_value_in_context;
end some_package;
/
exec some_package.set_value_in_context('foo');
select sys_context('some_context', 'some_attribute') from dual;
The value that was set for a context-attribute pertains to the current session only. Other sessions can have their own values, reconnecting «forgets» the value:
conn rene/rene;
select sys_context('some_context', 'some_attribute') from dual;
Accessed Global
Using the accessed globally modifier in the create context statement allows to set a value for an attribute globally, that is, other sessions see the set value as well and the value persists after reconnecting:
conn rene/rene
create context global_context using global_package accessed globally;
create package global_package as
procedure set_value_in_context(global_value in varchar2);
end global_package;
/
create package body global_package as
procedure set_value_in_context(global_value in varchar2) is
begin
dbms_session.set_context('global_context', 'global_attribute', global_value);
end set_value_in_context;
end global_package;
/
exec global_package.set_value_in_context('valid across sessions');
conn rene/rene
select sys_context('global_context', 'global_attribute') from dual;