There are basically four types of variables:
·
Session
· Repository
· Presentation
· Request
Session
Variables
Session variables are created and assigned a value when each
user logs on. When a user begins a session, the Oracle BI Server creates a new
instance of a session variable and initializes it.So, every login has its own
session variable.
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.
Session variables can only be created using the Oracle BI
Administration Tool
There are two types of session variables:
· System A session variable 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 (such as static or dynamic repository variables and
non-system session variables).Few system variables are (USER,PROXY,LOGLEVEL,PORTALPATH,
DISABLE_CACHE_HIT)
·
Non-system A system variable that the administrator
creates and names. A common use for non-system session variables is setting
user filters.For example, the administrator might create a Sales Region
non-system variable that initializes the name of a user's sales region.
Non-system
session variables can only be created using the Oracle BI Administration Tool.
Syntax
for Referencing Session Variable
“VALUEOF(NQ_SESSION.“VariableName”)”
A repository variable has a single value at any point in time.
Repository variables can only be created using the Oracle BI Administration
Tool
There
are two types of repository variables:
·
Static Repository variables whose value
persist and do not change until the administrator decides to change them. The
value of a static repository variable is initialized in the Variable dialog
·
Dynamic Repository variables
whose values are refreshed by data returned from queries. You also set up a
schedule that the Oracle BI Server will follow to execute the query and
periodically refresh the value of the variable.
Syntax
for Referencing Repository Variable
For displaying repository variables, we should use
“@{biServer.variables.VariableName}”
or “@{biServer.variables['VariableName']}”
For using repository variables in expression,we should use “VALUEOF(“VariableName”)” for
static variable and “VALUEOF(“Dynamic
Initialization Block Name”.“VariableName”)” for dynamic variable.
Presentation
Variables
A presentation variable is a variable that you can create as
part of the process of creating one of the following types of dashboard
prompts:
Column prompt presentation variable created as part of a column
prompt is associated with a column, and the values that it can take come from
the column values.
To create a presentation variable
as part of a column prompt, in the "New Prompt dialog" (or
Edit Prompt dialog), you have to select Presentation Variable in
the Set a variable field and then enter a name for the variable in
the Variable Name field.
Variable prompt presentation variable created as
part of a variable prompt is not associated with any column, and you define the
values that it can take.
To create a presentation variable
as part of a variable prompt, in the "New Prompt
dialog" (or Edit Prompt dialog), you have to select Presentation
Variable in the Prompt for field and then enter a name for the
variable in the Variable Name field.
Syntax
for Referencing Presentation Variable
For displaying presentation variables, we should us
“@{variables.VariableName}[Format]{DefaultValue}”
Format and DefaultValue are optional
Format is useful to format the data for e.g., for Date, format
can be MM/DD/YYYY. Note: Default Value is not formatted.
For using presentation variables in expression, we should use
“@{“VariableName”}{DefaultValue}”
Default value is optional
Request
Variables
A request variable lets you override the value of a session
variable but only for the duration of a database request initiated from a
column prompt. You can create a request variable as part of the process of
creating a column prompt.
Column prompt request variable that is created
as part of a column prompt is associated with a column and the values that it
can take come from the column values.
Variable prompt To create a request variable as
part of a column prompt, in the "New Prompt dialog" (or
Edit Prompt dialog), you have to select Request Variable in the Set
a variable field and then enter the name of the session variable to
override in theVariable Name field.
The value of a request variable
is populated by the column prompt with which it was created. That is, each time
a user selects a value in the column prompt, the value of the request variable
is set to the value that the user selects. The value, however, is in effect
only from the time the user presses the Go button for the prompt
until the analysis results are returned to the dashboard.
