HP Intelligent Management Center Standard Software Platform - Manual (Page 592)

• If you change the parameter from optional to mandatory, the HasValue()
function is not automatically removed from your formula.
Handling a parameter with no value
When the report engine evaluates any formula which references an optional
parameter that does not have a value, it generates a runtime error. All
formulas that reference an optional parameter should first use the HasVal
ue()
function to check if that parameter has a value before evaluating it.
This includes record selection formulas and saved data formulas.
Note:
The system will not automatically drop a statement from the SQL WHERE
clause. It is the report designer’s responsibility to decide which statement to
leave out based on HasValue() testing.
Understanding dynamic prompts
Both dynamic prompts and cascading lists of values are available in Crystal
Reports. These features let you populate the lists of values associated with
a prompt from a data source outside of your report. (Static lists of values that
are stored in your report are also available in Crystal Reports.)
This dynamic capability is available to all Crystal Reports users—whether
or not they have the added capabilities of BusinessObjects Enterprise. When
Crystal report files are stored in BusinessObjects Enterprise, additional
dynamic prompting features are available. The following table shows which
features are available with each product.
Note:
In the table, and elsewhere in this section, the term managed report is used
to describe reports that are stored in a BusinessObjects Enterprise
environment, while unmanaged report is used to describe reports that are
stored outside such an environment.
592 Crystal Reports 2008 SP3 User's Guide
Parameter Fields and Prompts 23
Understanding dynamic prompts