The system provides features to improve the integrity and consistency
of your data. Two ways to protect data are enforcing business rules and enforcing
data type rules.
You can enforce business rules using the following methods:
- Referential constraints let you put controls (constraints) on data in
files you define as having a mutual dependency. A referential constraint lets
you specify rules to be followed when changes are made to files with constraints.
- Triggers let you run your own program to take any action or evaluate changes
when files are changed. When predefined changes are made or attempted, a trigger
program is run.
The system performs data type checking in certain instances to ensure,
for example, that data in a numeric field is really numeric.
In addition, the system protects data from loss using the following methods:
- Journaling and commitment control functions
- System-managed access path protection (SMAPP) support