HP Storage Essentials Storage Resource Management Report Optimizer Software 6.0 Building Reports Using the Web Intelligence Java Report Panel (August 2008)

Building Reports Using the Web Intelligence Java Report Panel 49
Working with query contexts
When you create a query, or refresh a report, you may be asked to choose a context
before the query can run. In a universe, contexts are implemented to avoid ambiguous
data providers. This section describes what is an ambiguous query, how contexts are
used, and explains how you can choose a context to ensure that your query returns
relevant information.
What is an ambiguous query?
An ambiguous query is a query that contains one or more objects that can potentially
return two different types of information.
In a universe, certain dimensions may have values that are used for two different purposes
in the database. For example, the [Country] dimension in the query below can return two
types of information:
• Customers and the country in which they spent their vacation.
• Customers and the country for which they have made their reservation.
The role that Country plays in this query is ambiguous. A country value can be either the
country where a vacation was sold, or a country where a vacation is reserved. One is
existing information (sales), and the other is future information (reservations).
To avoid ambiguities in a query, the universe designer identifies the different ways that
objects can be used in the universe, and implements restrictions on how these objects can
be combined. These restrictions are called contexts.
What is a context?
A context is a defined group of objects that share a common business purpose. This
business purpose is usually the type of information that these related objects represent. For
example, a sales context is a grouping of all the objects that can be used to create sales
data providers. A reservations context is a grouping of all the objects that can be used in
reservation data providers. Contexts are defined in a universe by the universe designer.
You can combine any object within the same context to create a query. You can also
combine objects in different contexts. If you use an object that is common to both contexts,
Web Intelligence will try to determine the context that best fits the other objects in the
query.
If it can not determine a context, you are prompted to choose the context that you want to
apply to the query. For example, When you run the query above, a dialog box appears