Currently, developing an app that needs to synchronize its data between a server. The app heavily uses SQLite, so we moved to raw sqlite and decided to use FMDatabase. Our tables are denormalized and without keys because we do not manage data state, just gathering the data and sending it. We are updating the tables at some time interval (getting from a server and inserting new content) but sending data to the server is more frequent case.
Data from a server comes as full records with id values (char type GUID value), so we have made PK keys for the tables to consist of those id columns. The thing is, when getting data from a server, I need just to insert new records and currently, I’m making inserts with those id values. Some records get inserted (new) and some fail due to unique PK constraint on id columns. For me, it’s perfectly fine, just annoys messages in console (unique key violated) and not sure is it affecting performance and etc. I could loop through records before inserting new, to find existing ones and to insert only really new records but I think it’s a waste.
Also, I could make explicit internal int id (faster for PK index) but our tables are not related with FK, so it would be redundant. Any thoughts on that?
The INSERT statement comes with optional ON CONFLICT clause, so if you want to suppress the warnings, simply use INSERT OR IGNORE and the duplicated PKs will be ignored.