Maciej Sobczak <prog <at> msobczak.com> writes: Thank you for your quick reply.
There is also a third option here, probably most generic - expose the whole stream object, so that users can play with it on their own; this goes far beyond locale control, you can even replace the whole streambuf there. I don't see any immediate use for this, but we didn't foresee the locale issue either.
Still think it would better if the backend decides how numbers, dates etc should be formatted in the sql string.
why not have a "intonull" expression that take a second nullValue argument: sql << "select a,b,c,d... from tbl", intonull(vara, ""), intonull( varb, -1)...
First note: you don't have to create indicator vars if you don't expect nulls. Second, the above assumes that you have some default value to replace the null. Isn't there a dedicated SQL function for this?
I often run into databases where string fields can both be empty and null with no difference in meaning (just bad design). COALESCE is possible but I think the null handling should be in the code not in the sql statement. What I'm asking for is just some syntactic sugar.
What about:
sql << "select ...", into(a, default("")), into(b, default(-1));
The point is that there is already a framework for extending into elements this way.
Yes that would be ok. (default is a reserved word but I understand what you mean).
sql << "select x from tbl", into(a); if (!sql.empty()) // something was fetched
or sql << "update tbl set x = 2 where y = 3"; if (sql.rowsaffected() == 0) // not found
Yes, that's one possible approach. Boost.optional would handle the rest. We have to review this subject.
Another approach could be to follow the stream syntax with eof() and bad().