I am currently working on a shapefile dataset for france that exists for different administrative levels. The problem is that in the region I am looking at there has been a reform in the last year and the dataset is from 2015, so the administrative level (level 3) I am looking at is not correct anymore so that I would have to model it from merging polygons of level 4 by myself. This would be no problem doing it by merging and dissolving, but 90 polygons of level 4 make up one of level 3 so this would take an incredibly long time for the whole of france. The dataset is connected to a table that works with the french INSEE numbers for each polygon. Now I know where to get data that tells me which polygons/INSEE numbers would go together, but I don't really know how to connect the tables in order to easen up the workflow. The INSEE numbers are one attribute they both share but I do not know how to connect those tables now.
I hope this question is somehow understandable - I can't figure out how to export the table correctly, but it really is only the FID, the INSEE and the name of the administrative area plus shape area, whereas the other table would have to be crated from scratch and would only be name of the administrative area plus INSEE number.
Greetings and thank you very much,