In this section,we are trying to explain Handling of table data in R12.2 online patching using oracle edition based redefinition(forward cross edition triggers)
Suppose the patch has to modify the column Description from Mixed Case to Upper case
Table A has Existing Description column has values of (red,ORANGE…)
The requirement from patch is
Description column has upper case values of (RED,ORANGE…)
Steps done in Online Patching
•Create a new Description#1 in the table when you patch the table
•Create patch Editioning View Maps:
RUN – Description => Description
PATCH – Description => Description#1
Now Next step is to populate Description#1 from Description# which is achieved using forward cross edition triggers
What is Forward Cross edition triggers?
1)Forward cross edition triggers are database triggers which works across edition.
2)Forward cross edition triggers is used to sync data as part of online patching process.
3)When the patch is applied ,it sync up the data fro mixed case to upper case. Now the data changes done from patching to cutover time are populated to new column by forward cross edition triggers
4)They Provide the logic to synchronize and transform data between run and patch editions storage columns
5)In summary these are used to upgrade both existing data and ongoing changes that occur while run edition is in use.
6)It Allows the Run Edition code to signal that a data upgrade is required and Fires in response to an insert, update of table
7)In this particular case it upgrade the column “Description” from mixed to upper case
Running Application still sees the column data as mixed case
Patched Application sees the column data as upper case