Re: [boost] sqlpp11: SQL for C++

On Tue, Nov 12, 2013 at 7:16 AM, Roland Bock wrote:

On 2013-11-12 04:26, Tim Keitt wrote:

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On Sat, Nov 9, 2013 at 4:03 PM, Roland Bock wrote:

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This is an interesting thread and I thought I'd comment.

I am a pretty heavy user of postgresql/postgis (spatial extension) in my work. I wrote the first R package to access postgresql and contributed to the current R DBI package. I did a proof-of-concept (= not very pretty ;-) embedding of the Boost Graph Library in postgresql replacing local storage with prepared queries called on demand.

I have to say when I look at this, I don't really want to learn another SQL. I am perfectly happy to send query strings to the database and let it parse them. I can debug these separate from my C++ code. I think for complex queries (recursive with anyone?) it would be quite difficult to get the C++ right. Could you send me a complex/recursive example? I'd be interested in a comparison, of course.

Example here http://jakub.fedyczak.net/post/postgresql-with-recursive-tree-traversing-exa...

The debugging topic is interesting. Obviously, sqlpp11 can be used to print query strings. The current connectors do that, when used in debug mode.

Personally, I believe that the way that sqlpp11 yields results (members of a struct instead of positional entries in a container) and the compiler support in constructing and maintaining queries outweigh having the exact textual representation of the query in the source code. But that is certainly a matter of taste.

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What I would really like is a mapping of binary cursors to iterator concepts + easy type-safe endian-aware customizable data conversion. But that's my bias. I've always liked mapping on-demand data to common interfaces.

I'll have to read up on binary cursors, that is not my core competence...

Cursors are not difficult: DECLARE the_cursor CURSOR FOR SELECT ... Lets you iterate through the results. Binary cursors return the binary representation as used in the server, which may be different from the client. THK

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But your use cases are probably different and I can see how this would be very useful to some.

Thanks and regards,

Roland

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