Does anyone know know where I can find protocol information on how to connect to
a MySQL database directly using UNIX sockets (without using libmysqlclient.so)?
I haven't had any luck googling it.

On 9/29/2010 7:44 AM, Rob wrote:
You won't - the socket is used internally by MySQL for communications
between the application and the server. What you would need to do is
duplicate the function of libmysqlclient.so, which would be a huge job
(and may change with a different release of MySQL). So you might as
well use libmysqlclient.so (unless you're a glutton for punishment, that
is).

--
==================
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Jerry Stuckle
JDS Computer Training Corp.
jstucklex (AT) attglobal (DOT) net
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Rob wrote:
Why not just grab the sources and see..

http://dev.mysql.com/downloads/mysql/5.5.html

Rob <junkmail3 (AT) lavabit (DOT) com> wrote:

Here: http://forge.mysql.com/wiki/MySQL_In...erver_Protocol

But why? Are you aware of

http://dev.mysql.com/doc/refman/5.1/en/connector-c.html

?


XL

The Natural Philosopher wrote:
Yeah, there looks to be more to this than I thought: as Jerry noted, this could
be a huge job. I guess I could use the source code and modify it to suit my
purposes but it still would be a big job.

Thanks,
Rob

Axel Schwenke wrote:
Thanks - that looks like what I was looking for. It looks to be a bigger job
than I thought though: I really wasn't thinking about authentication.

What I am trying to do is add some database connectivity to some of my CGI
programs. The problem is that they do not use the C standard library (instead
using the Linux API directly) and I'm not sure if pulling in a library will work
(anybody know? The next step probably just have to test and see if it works.)
properly.

I think the approach I am going to take for now is to write a daemon that uses
libmysqlclient.so - I needed an excuse to learn C a little better anyway. ;-)
That way I can probably also cache some data and would give me a database
"abstraction layer" as I would also like to be able to connect to a MS SQL
Server database at some point in the future too.

If anyone knows a better approach, I'm open to suggestions. This is the first
time I've tried to write a database application, so I'm basically learning from
scratch.

Thanks,
Rob

On 10/1/2010 7:38 AM, Rob wrote:
First of all, use the standard C library. Much better than making
direct Linux calls, and not significantly additional overhead.

But just because you're using Linux calls in your application doesn't
mean your C libraries aren't loaded and running. They are, as they are
used for all kinds of internal stuff. And it doesn't mean you can't use
the MySQL client libraries.

--
==================
Remove the "x" from my email address
Jerry Stuckle
JDS Computer Training Corp.
jstucklex (AT) attglobal (DOT) net
==================

Rob wrote:
well Its not clear what the constraints are on your client apps.

So its hard to suggest an optimal route.
At some level you are going to need some kid of library to just e.g.
open a socket with.

I am not exactly clear as to what you men by using the Linux API
directly..do you then have your OWN replacement for libc etc?
What the kernel has is pretty basic..and you still need a library of soe
sort to 8uinterface to it.

Of that is what you ARE doing, then the connector.c stuff may well be a
good place to start to roll your own access library. And then write such
stubs as it needs from other libraries to get a working DB access shim..

I get the impression these are embedded clients, and you want to keep
code bloat as low as possible..I've done this and it usually helps to
write your own stripped down libc and stdlib and so on..or as much of it
as you are going to need, anyway. You a lift as much as is needful from
elsewhere of course, but in the end you have to take a clear cut
decision as to whether you use someone elses code, and accept their
bloat and generality, or spend the effort adapting or rewriting it, to
get it to be what you want, and no more, and no less.

Knowing what your constraints are, would help to indicate which approach
is more rational, but it is your decision in the end..

Rob <junkmail3 (AT) lavabit (DOT) com> wrote:
The bigger problem is the correct handling of all the optional features
and changes between versions.

If you link with libmysqlclient, you also need to link several more
system libs. I.e. for a standard 5.1 build:

$mysql_config --libs
.... -lmysqlclient -lz -lcrypt -lnsl -lm

I also don't see the point in writing CGI programs without using any
system libs (besides the "fun factor" of course). CGI itself is already
so inefficient, that any savings with regards to libraries make little
sense.

This sounds strange and I wonder what kind of problem you're trying to
solve that way. I.e. "database abstraction" does not work very well
except for some showroom cases.

If you want to use a generic API to access your database, you could
go for ODBC. And/or have a look at http://sqlrelay.sourceforge.net/

First you should check for alternatives to CGI. Have a look at FastCGI.
Or any API that your HTTP server might have (i.e. APAPI for Apache).
Writing Apache extensions is pretty easy and fun!


XL