c-treeACE V10.0 Update Guide

Data Filter Stacks

A significant extension to existing data record filter support takes filtering to a new level. Now you can “stack” data record filters over the same data file. Layering conditional expressions at run-time provides extensive power.

Often in an application’s logic, data read requirements might be located in different areas of your code and necessitate different criteria. You might establish a data filter in one location and need additional filtering elsewhere. Say you establish a filter based on user at logon, then later in the application, a date is introduced. With the ability to “stack” your data file filters, you can add the required filter when you need it.

Filters provide an efficient way to mask what you see in a file:

• Powerful regular expression support for filters
• Stack multiple data filters on the same file
• Conditional expressions: reference any section of the record (offset, length)
• Create a filter when no schema is defined in the file resource (no DODA)
• Filter user-defined callbacks
• Permanent System-Wide File Filters
• Fast low-level (server-side) compare routines

For more information, see Data Filters.