exportresults_helper.php
A Survey object may be loaded from the database via the SurveyDao (which follows the Data Access Object pattern). Data access is broken into two separate functions: the first loads the survey structure from the database, and the second loads responses from the database. The data loading is structured in this way to provide for speedy access in the event that a survey's response table contains a large number of records.
The responses can be loaded a user-defined number at a time for output without having to load the entire set of responses from the database.
The Survey object contains methods to conveniently access data that it contains in an attempt to encapsulate some of the complexity of its internal format.
Data formatting operations that may be specific to the data export routines are relegated to the Writer class hierarcy and work with the Survey object and FormattingOptions objects to provide proper style/content when exporting survey information.
Some guess work has been done when deciding what might be specific to exports and what is not. In general, anything that requires altering of data fields (abbreviating, concatenating, etc...) has been moved into the writers and anything that is a direct access call with no formatting logic is a part of the Survey object.
- elameno