Forms and Reports—The Basics - Beginning Oracle Application Express 4.2 - page 123

The values of all APEX items, both page items and application items, are tied to this unique session identifier.
This identifier is referred to as the APP_SESSION_ID . You can see the session identifier in the URL of most pages in an
APEX application. It's highlighted in Figure 6-42 .

Figure 6-42. APEX session identifier in an APEX URL

Setting and Retrieving Session State
Session state is set by user-input items, computations, processes, and PL/SQL code. In PL/SQL, when within an APEX
process, you can set an item equal to a value, like so:

:P1_ITEM_NAME := 'some value';

In PL/SQL, when in a stored procedure, you can use the apex_util.set_session_state procedure to set a value
in session state:

apex_util.set_session_state( 'P1_ITEM_NAME', 'some value');

The syntax to retrieve session state for an item varies according to where you're referencing the item.
In templates or regions, tabs, menus, or lists, use the following substitution-string syntax (and don't forget the
trailing dot!):

&P1_ITEM_NAME.

Use the following syntax in SQL statements:

:P1_ITEM_NAME

From PL/SQL, use one of the following two options depending on what type of block or program unit you're in:

Anonymous PL/SQL block: :P1_ITEM_NAME
PL/SQL Unit Called from APEX: V('P1_ITEM_NAME')

Within conditions, use this syntax:

P1_ITEM_NAME

■ the V function just mentioned is an ApeX-provided function that retrieves the session-state value of an ApeX item.
exercise caution when using this function, because using it in a stored program unit could introduce performance issues.

Note

Viewing Session State
To view session state, click the Session link on the Developer toolbar. You should see a page like that in Figure 6-43 .
Then use the Page, Find, and Views parameters to view session state for the application. The drop-down View menu
shown in Figure 6-44 allows you to view Page Items, Application Items, Session State, Collections, and All of the above.