Kbase P122121: What are the different types of CRC?
| Autor |
Progress Software Corporation - Progress |
| Acesso |
Público |
| Publicação |
9/5/2007 |
|
Status: Unverified
GOAL:
What are the different types of CRC?
GOAL:
What is the _trig-crc?
GOAL:
What is the _file._crc?
GOAL:
What is the _Index._idx-crc?
FIX:
1.) The Trigger CRC
The _trig-crc value is computed from the code implementing the Database trigger.
The purpose is to prevent a trigger from being substituted by another one that does something different.
2.) The File CRC
The _file._crc is a crc composed of information about the field definitions (position, data type, etc.) for the record layout of a table.
In Progress Version 9.x, the position used is the logical position, not the actual storage position.
3.) The Index CRC
The _Index._idx-crc is a crc of the index key definition. It used to be combined with the file crc before Progress Version 9.x, but since Progress Version 9.x is separate.
This allows adding new indexes and deleting old indexes without requiring a recompile.