Hi,
Theoretically speaking the challenge in this is not the excecution, nor the coding required. Your main issue will be, that the data has to be extracted out of one table and has to be moved to another one.
This results in the lost of any references (e.g. incident->cmdb_ci). The only way of preventing this is by keeping the unique ids (in this case sys_ids, except if you changed it before). This again should theoretically work, since the sys_id has to be unique up to the top level (cmdb). BUT it would mean, that on inserting the extracted data, the "old" one has to be already gone. This by it self is a huge risk, since it allows a timeframe where data could potentially drop since it has to be nonexisting the moment you insert it again.
Therefore the times i had costumers do this, they copied it instead. BUT that also ment that the same sys_ids could not be used (which is not that good of an idea anyways).
So to get around the above mentioned conundrum the script that handles the data migration should also check all references and update them. The scripts workflow would match something like this:
get all the cis to move => copy them => replace references => deactivate the "old" cis
This (depending on the amount of data) ist time consuming and should be done one ci at a time (to reduce pontential damage in case of a shut off/down).
Other than that i would generally dissaprove to delete classes.
I hope i could help.
Greetings
Fabian
