Xemuth wrote on Tue, 05 March 2019 07:23

And, if one of best way is storing data into Xml/Json, do you know if Upp have a Mechanism allow us to retrieve some
particulare data really quickly from this XML like an sql requete would do on a classic database ?

IMHO, if your data has a fixed structure, then the best way to store data is a database. It can be an embedded database like Sqlite or FirebirdSQL.
If your data is read-only or has no structure, then XML or JSON should be your choice.
If you have a lot of data, you can store it in a multi-stream bz2 archive similar to Wikipedia dump.
In case you are not using a database you'll need to implement a simple one by yourself. This is not that difficult because you can create all needed indices in memory and serialize them in binary/XML/JSON format. It is very easy to serialize/deserialize data in Upp.

Hope this helps.