Session Variables in OBIEE

Session variables are similar to dynamic repository variables in that they obtain their values from initialization blocks. Unlike dynamic repository variables, however, the initialization of session variables is not scheduled. When a user begins a session, the Oracle BI Server creates new instances of session variables and initializes them.

Session variables are primarily used when authenticating users against external sources such as database tables or LDAP servers. If a user is authenticated successfully, session variables can be used to set filters and permissions for that session.

System Session Variables

System session variables are session variables that the Oracle BI Server and Oracle BI Presentation Services use for specific purposes. System session variables have reserved names, that cannot be used for other kinds of variables.

When you use these variables for Oracle BI Presentation Services, preface their names with NQ_SESSION. For example, to filter a column on the value of the variable LOGLEVEL set the filter to the Variable NQ_SESSION.LOGLEVEL.

The available system session variables are.

DISPLAYNAME:

Used for Oracle BI Presentation Services. It contains the name that will be displayed to the user in the greeting in the Oracle BI Presentation Services user interface. It is also saved as the author field for catalog objects. For internal Oracle BI repository users (nondatabase users), this variable is populated with the user's full name.

EMAIL:

Contains the user's default email address for use with Answers. If the delivery option of Answers is enabled, an email device using this address will be created for the user upon first log in. Users can override this address by changing their account settings in Oracle BI Presentation Services.

GROUP:

Contains the groups to which the user belongs. These are used by both the Oracle BI Server and Oracle BI Presentation Services.When a user belongs to multiple groups, separate the group names with semicolons. Do not delimit text (for example, do not surround the text with single or double quotes). Use a Varchar column in a database table to contain the group memberships.

For example, if a user belonged to groups called Sales US, Sales UK, QA and Dev, and Doc, the text entered into a Varchar data type column in a database table would be:

Sales US;Sales UK;QA and Dev;Doc

Note: The Oracle BI Presentation Services Administrator needs to make sure that the names of Presentation Services groups are different from any user IDs that will be used to log on to Oracle BI Presentation Services. If a user and a Presentation Services group share the same name, the user will receive an Invalid Account message when attempting to log on to Oracle BI Presentation Services.

LAST_SYNCH_TIME and THIS_SYNCH_TIME:

These two variables are set and tracked by Oracle BI Presentation Services to manage the synchronization of Oracle BI Disconnected Analytics. For more information, refer to Oracle Business Intelligence Disconnected Analytics Administration and Configuration Guide.

LOGLEVEL:

The value of LOGLEVEL (a number between 0 and 5) determines the Logging level that the Oracle BI Server will use for user queries.

This system session variable overrides a variable defined in the Users object. If the Administrators Users object has a Logging level defined as 4 and the session variable LOGLEVEL defined in the repository has a value of 0 (zero), the value of 0 applies.

PORTALPATH:

Used for Oracle BI Presentation Services. It identifies the default dashboard the user sees when logging in (the user can override this preference after logged on).

REQUESTKEY:

Used for Oracle BI Presentation Services. Any users with the same nonblank request key will share the same Presentation Server cache entries. This tells Oracle BI Presentation Services that these users have identical content filters and security in the Oracle BI Server. Sharing Presentation Server cache entries is a way to minimize unnecessary communication with the Oracle BI Server.

SKIN:

Determines certain elements of the look and feel of the Oracle BI Presentation Services user interface. The user can alter some elements of the user interface by picking a style when logged on to Oracle BI Presentation Services. The SKIN variable points to an Oracle BI Presentation Services folder that contains the nonalterable elements (for example, graphics such as GIF files). Such directories begin with sk_. For example, if a folder were called sk_companyx, the SKIN variable would be set to companyx.

USER:

Holds the value the user enters as his or her logon name.

WEBGROUPS:

Specifies additional groups specific to Oracle BI Presentation Services, if any. The use of Presentation Services groups provides a mechanism for more granular content control.

Non-system Session Variables

The procedure for defining nonsystem session variables is the same as for system session variables.

A common use for nonsystem session variables is setting user filters. For example, you could define a nonsystem variable called SalesRegion that would be initialized to the name of the user's sales region.

You could then set a security filter for all members of a group that would allow them to view only data pertinent to their region.

When you use these variables for Oracle BI Presentation Services, preface their names with NQ_SESSION. For example, to filter a column on the value of the variable SalesRegion set the filter to the Variable NQ_SESSION.SalesRegion.

Step by step process of creating session variables..

     1.  From the Administration Tool menu bar, choose Manage > Variables.

    2.  In the Variable Manager dialog box, from the menu bar, choose Action>New>Session>Variable.

3. In the Session Variable dialog box, type a variable name.
   Names for all variables should be unique. The names of system session variables are reserved and cannot be used for other types of variables.

     For session variables, you can select the following check boxes:

4. --Enable any user to set the value:
   Check box that allows you to set the session variables after the initialization block has populated the value (at user login) by calling the ODBC store procedure NQSSetSessionValue(). For example, this allows non-Oracle BI Administrators to set this variable for sampling.
   --Security Sensitive:
   Check box that identifies the variable as sensitive to security for virtual physical databases (VPD). When filtering cache table matches, the Oracle BI Server looks at the parent database of each column or table that is referenced in the logical request projection list. If the physical database source is a VPD, the Oracle BI Server matches a list of security-sensitive variables to each prospective cache hit. Cache hits would only occur on cache entries that included and matched all security-sensitive variables.
5. Use the Initialization Block drop-down list to select an initialization block that will be used to refresh the value on a continuing basis.
   
   
   
   To create a new initialization block, click New.
6. To add a Default initializer value, perform one of the following steps:
   • To use the Expression Builder, click the ellipsis button to the right of the Default initializer work space.
   • Type the value into the Default initializer text box.
7. Click OK.