My understanding is the keys in the info_table need to change. That causes the very expensive update in the update in the data tables. No?
The keys in the info_table need to change because their contents are no longer legal to be stored (OP has not specified but think using an integer value of someones social security number as a key). The FK side of the relationship equality has the same illegal data values problem and need to be changed too.
Wow, I couldn’t disagree more ;)
Your agreement or disagreement with the problem statement is immaterial here - the OP has stated what the requirement, for which I have made a simplistic analogy in order to try and get the point across to you. As the OP has said it is a poor design - and now it is being corrected. The request is whether there is some way to do so better than the two options the OP already described.