Thanks for the long & detailed review. I got a few minor comments below.
Thanks - and also sorry for the layout of the review, I had it earlier locally but it didn't take over all lists etc correctly.
With a struct in C++ (this is really cool!) (it would also be cool if a struct could be inserted!)
Do you mean using the member of the structs by name for a parametrized query?
Yes! I realize this goes into the direction of a ORM. But you have it for a select query as well. So this would be nice (now, in the future, or maybe it doesn't fit in the library approach): struct query_result { int64_tid; std::string regio_name; int64_t population; double latitude; double longitude; }; auto stat = conn.prepare("insert into italy (regio_name, population, latitude, longitude) values (?1, ?2, ?3, ?4)"); query_result qr{0, "Calabria", 1947131, 38.905, 16.5944}; stat.execute(qr);
This is probably a subtype, which would make a great example for custom conversions. Are you using spatialite?
No, I'm using a geopackage. But it's similar, it's sqlite including geometry. https://en.wikipedia.org/wiki/GeoPackage
2: Samples how to use JSON. Do we really need it in this library? Isn’t it an extension that can be documented, but not included? That would also avoid a dependency.
I have used json data extensively in sqlite and it's usually enabled by default these days, so I think it's a good default to enable it.
All right, clear
3: Samples how to use BLOB I had to inspect the unit test for it What is open_blob ?
You can open a blob field directly without a query and read it's data. That can be especially advantageous if you just want to access part of it.
Then it would be nice if it is documented, including a sample!
5: The tag_invoke should be explained better. Why do we need it? How do we define it? A sample would be very welcome. I ignored it further, so maybe I don’t need it. Or did I need it for described structures with blobs?
You need it for custom conversions. It's in the url example, but under documented.
All right! Cheers, Barend