Keeping track of information state

[JLehr]

In the IT Advisor ETL solution, just about any piece of information can be in one of four different states at any point in time:

The states are: NEW, CHANGED, DELETED, SYNC_DELETED and SYNCED. 

In the typical life-cycle, information starts in the NEW-state.

IT Advisor will pick up the information as new, interpret the information and add it to the IT Advisor model. Once the information has been read into IT Advisor, it will be moved to the SYNCED-state.

When the information is updated from the external system, the state of the information should be set to CHANGED. 

When IT Advisor synchronizes its information, the changes will be reflected in the IT Advisor model. If the external system decides to remove a piece of information it should be moved to the DELETED state. IT Advisor will subsequently handle cleanup of the information inside IT Advisor and report back the state SYNC_DELETED. 

The state-system is primarily used to speed up the process of synchronizing data from the staging database to the IT Advisor internal database. Only data/information in the NEW or CHANGED state are expected to contain information that is not already known by IT Advisor, so only those are read and synchronized.

Note: Information in the SYNCED, SYNC_DELETED, and DELETED states will not be read by IT Advisor, and subsequently changes to the information will not be updated into IT Advisor. 

Tracking Data Information State in Export Data

The export database uses the same strategy for keeping track of the state of data, as the import database, with the one exception, that the data will never be marked as synced.

The red arrows represent state-changes made by the external system, either through direct data manipulation or through a transformation. The green arrows represent state-changes made by IT Advisor as part of the synchronization of information.