HistHook Function Reference

This section describes the HistHook Export functions in detail.

Note:
- The string length of the SQL query is limited to 997 characters. If the number of characters supplied in the SQL query exceeds the limit, the HistHook interface does not work.
Also, it is recommended that you add appropriate exception handling in the implementation code. An exception in the hook can possibly cause the calling application to terminate.

- When you upgrade to AVEVA Batch Management 2023 R2, new process field values (HighDeviationValue, LowDeviationValue, HighLimitValue, LowLimitValue) for Process Variable and (HighDeviationValue, LowDeviationValue) for Material Input are stored in the database. If you do not want to use these new process field values, then perform the following:
a. Back up the existing HistHook.dll.
b. Upgrade to AVEVA Batch Management 2023 R2.
c. Replace the backed up HistHook.dll in the Bin folder.


- All the below functions return NULL value if alternate SQL statement is not provided. When a function returns NULL value, the default implementation is invoked.