We are upgrading our systems for IDNA support but I'm currently struggling with our domain search. In our domain portfolio you can search for domains. IDNA domains are saved as their A-label in our database (café-modern.com is saved as xn--caf-modern-d7a.com) and we just convert it to the U-label when displaying it in the browser.
Problem is that this totally breaks our search.
When someone searches for café-modern.com I can easily convert it to the IDNA value and use that in the WHERE domain_name LIKE ? part of the DB-query but when someone searches just for café (xn--caf-dma) that should also find café-modern.com
A solution would be to save both the A-label and U-label values in the database but that's somehing I would want to keep as a last resort because the dataset is quite large and I would like to keep the database schema as simple as possible.
It is so normal. I have been using a similar system. I think your design is incorrect. Should not save as like (xn--caf-modern-d7a.com), You can save as like (café-modern.com) on DB. You have to convert from IDNA value to UTF8 value(or another one) when you are recording on DB. Thus, you can search café-modern.com and café in the WHERE domain_name LIKE ?