Using Your Own Filters
Go Up to Filtering Blob Data
Unlike the standard InterBase filters that convert between subtype 0 and subtype 1, an external Blob filter is generally part of a library of routines you create and link to an application.
You can write Blob filters in C or Pascal (or any language that can be called from C). To use your own filters, follow these steps:
- Decide which filters you need to write.
- Write the filters in a host language.
- Build a shared filter library.
- Make the filter library available.
- Define the filters to the database.
- Write an application that requests filtering.
Steps numbered 2, 5, and 6 are described in greater detail in the following sections.