approaches for SCD

[cetzhbo]

Hello Gurus,

I want to summarize the approad to develop SCD .

(1) using transform stage to capture change , to implement change.( including insert/delete/update)

(2) using change capture stage/change apply

(3) using scd stage

is there any other approach to implement SCD ?

thanks very mcu!

[ray.wurlod]

Yes. Change capture can be done externally to DataStage. Read about IBM's acquisition last year of Data Mirror, and search the web for other techniques such as processing transaction logs.

[vmcburney]

I think there is two types of change capture. There is the original change capture of changes to the source system that products like InfoSphere Change Data Capture (formerly Data Mirror) is good at, then there is change data determination. Checking to see if the source system change requires a change to the target dimension. This should be handled by the new Slowly Changing Dimension stage - it does the lookup against the target and works out what changes need to be applied to the target dimension.

[chulett]

Yes, two types: CDC and CDD. I've always known the latter as Change Data Dectection but the description still holds. CDC happens at the source while CDD is performed 'outside' the source or at least outside of any official CDC mechanism.