Siebel Analytics Server Administration Guide > Using Variables in the Analytics Server Repository > Using the Analytics Variable Manager >

Using Repository Variables

A repository variable has a single value at any point in time. Repository variables can be used instead of literals or constants in expression builders in the Administration Tool. The Siebel Analytics Server will substitute the value of the repository variable for the variable itself in the metadata.

This section includes the following topics:

• Static Repository Variables
• Dynamic Repository Variables

Static Repository Variables

The value of a static repository value is initialized in the Variable dialog box. This value persists, and does not change until a Siebel Analytics Server administrator decides to change it.

Example

Suppose you want to create an expression to group times of day into different day segments. If Prime Time were one of those segments and corresponded to the hours between 5:00 PM and 10:00 PM, you could create a CASE statement like the following:

CASE WHEN "Hour" >= 17 AND "Hour" < 23 THEN 'Prime Time' WHEN... ELSE...END

where Hour is a logical column, perhaps mapped to a timestamp physical column using the date-and-time Hour(<<timeExpr>>) function.

Rather than entering the numbers 17 and 23 into this expression as constants, you could use the Variable tab of the Variable dialog box to set up a static repository variable named prime_begin and initialize it to a value of 17, and create another variable named prime_end and initialize it to a value of 23.

Using Variables in Expression Builders

After created, variables are available for use in expression builders. In an expression builder, click on the Repository Variables folder in the left pane to display all repository variables (both static and dynamic) in the middle pane by name.

To use a repository variable in an expression, select it and double-click. The expression builder will paste it into the expression at the active cursor insertion point.

Variables should be used as arguments of the function VALUEOF( ). This will happen automatically when you double-click on the variables to paste them into the expression.

For example, the following CASE statement is identical to the one explained in the preceding example except that variables have been substituted for the constants.

CASE WHEN "Hour" >= VALUEOF("prime_begin")AND "Hour" < VALUEOF("prime_end") THEN 'Prime Time' WHEN ... ELSE...END

NOTE:  You cannot use variables to represent columns or other repository objects.

Dynamic Repository Variables

You initialize dynamic repository variables in the same way as static variables, but the values are refreshed by data returned from queries. When defining a dynamic repository variable, you will create an initialization block or use a preexisting one that contains a SQL query. You will also set up a schedule that the Siebel Analytics Server will follow to execute the query and periodically refresh the value of the variable.

NOTE:  When the value of a dynamic repository variable changes, all cache entries associated with a business model that reference the value of that variable will be purged automatically.

Each query can refresh several variables—one variable for each column in the query. You schedule these queries to be executed by the Siebel Analytics Server.

Example

Dynamic repository variables are very useful for defining the content of logical table sources. For example, suppose you have two sources for information about orders. One source contains recent orders and the other source contains historical data.

You need to describe the content of these sources on the Content tab of the Logical Table Source dialog box. Without using dynamic repository variables, you would describe the content of the source containing recent data with an expression such as:

Orders.OrderDates."Order Date" >= TIMESTAMP '2001-06-02 00:00:00'

This content statement will become invalid as new data is added to the recent source and older data is moved to the historical source. To accurately reflect the new content of the recent source, you would have to modify the fragmentation content description manually. Dynamic repository values can be set up to do it automatically.

Another suggested use for dynamic repository values is in WHERE clause filters of logical table sources, which are defined on the Content tab of the Logical Table Source dialog box.

The values of dynamic repository variables are set by queries defined in Variable Initialization blocks. When defining a dynamic repository variable, you create an initialization block or use a preexisting block that contains a query. You also set up a schedule that the Siebel Analytics Server will follow to execute the query and periodically refresh the value of the variable.

A common use of these variables in the Web is to set filters. For example, to filter a column on the value of the dynamic repository variable CurrentMonth set the filter to the Variable CurrentMonth.