HP Intelligent Management Center Standard Software Platform - Manual (Page 750)

Overview
Crystal Reports uses a three-pass reporting method to generate reports.
The sections below describe what happens during each step of this process.
To see a visual representation, refer to the flow-chart at the end of this
section.
What is a "pass"?
A pass is a process that Crystal Reports uses each time the data is read or
manipulated. Depending on the complexity of the report Crystal Reports may
make 1, 2, or 3 passes over the data. This feature allows for complex
reporting and formula manipulation.
Pre-pass 1
When previewing a report, the first elements to be evaluated are "constant"
formulas. Constant formulas are those that have a constant value for the
entire report. They do not change from record to record. For example, 100*
30 would be a constant formula. Constant formulas are evaluated at the
beginning of the print generation process and are never evaluated again.
This process is known as "BeforeReadingRecords." If you were to place a
constant formula field (i.e., 100*30) in the Details section, the result would
be 3000 for each record displayed.
Pass 1
After the "BeforeReadingRecords" process has taken place, Crystal Reports
begins reading the database records. During the record reading process,
the following will occur:
• Record retrieval. Where possible record selection and sorting are pushed
down to the database in this step.
• Evaluation of recurring formulas. These formulas are those that contain
database fields but do not contain references to subtotals or summary
information. This evaluation time is known as "WhileReadingRecords."
750 Crystal Reports 2008 SP3 User's Guide
Report Processing Model A
Overview