RuleFrame and BR's that should be handled the PRE or before triggers.

Question

When a business rule must be handled before INSERT/UPDATE/DELETE of an record, it looks to me like it cannot be implemented using a CAPI.
For example the following BR:
'When value of column is NULL use default value retrieved from other column.'
Do I have to defer from CAPI implementation and use TAPI to implemented this BR in PRE-TRIGGER? Or is there a better way that fits more in the CAPI structure??
Regards,
Sebastiaan

Answer 1

Sebastiaan,
From the CDM Standards & Guidelines Library, volume 2, chapter 7:
"However some change event rules should be implemented using the derivation expression mechanism given in Oracle Designer. This mechanism should be used when a value within the inserted or updated record must be derived or calculated as before the data is written to the database. [...] If more complex derivations are required, you will probably choose to create a derivation function as part of the Custom API, and then call this function in the derivation expression. Note that you must then set the
derivation expression type to Function Call."
For default values you may be able to use the Default Value property of a column (can also be a CAPI function call). However, it will only be applied if that column was not included in the insert call to the TAPI. Otherwise, you will have to use the Derivation Expression, and in the CAPI function you will then have to make sure that it is not executed during update, for example:
if g_inserting
then
return 100000;
else
return p_total_prj_limit;
end if;
Hope this helps,
Sandra