== MySQL client

=== Description

A small MySQL client library for chicken-scheme. This egg makes it possible to execute an SQL query on a MySQL database.

=== Authors

A. Carl Douglas

=== Requirements

Requires MySQL database system development components,
libmysqlclient and mysql_config.

The {{mysql_config}} program needs to be in the {{$PATH}} so the linker can find the native MySQL libraries.

On a Linux machine, consider trying:

  apt-get install libmysqlclient-dev

The mysql-client egg also has a runtime dependency on the regex egg.


=== API

<procedure>(make-mysql-connection hostname username password schema)</procedure>

This procedure will return a procedure that contains a closed off MySQL connection and can execute a query when called.

=== Examples

Here is a trivial example:

  (use mysql-client)
  (define mysql (make-mysql-connection "localhost" "root" #f "information_schema"))
  (define fetch (mysql "SELECT * FROM schemata"))
  (display (fetch))
  (newline)


Here is an example that will use the {{mysql_real_escape_string}} MySQL function to safely escape parameters in the query string using a placeholder syntax. In this case, the first argument is a string containing an SQL query, and the second argument will be an association list where the key represents the placeholder symbol in the query.

  (use mysql-client)
  (define mysql (make-mysql-connection "localhost" "username" "secret" "database"))
  (define fetch (mysql "SELECT * FROM t1 WHERE c1 = '$1' OR c2 = '$2'" 
                       '(($1 . "value 1';' ;")($2 . "value 2'; drop database; "))))
  (display (fetch))
  (newline)


For power users, to access directly the MySQL connection object pointer, pass a procedure to the MySQL client closure.

  (use mysql-client)
  (define mysql (make-mysql-connection "localhost" "username" "secret" "database"))
  (define fetch (mysql (lambda(c)(printf "~S ~%" c))))
  (display (fetch))
  (newline)

=== License

Copyright (C) 2012, A. Carl Douglas
All rights reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:

Redistributions of source code must retain the above copyright notice, this
list of conditions and the following disclaimer.
Redistributions in binary form must reproduce the above copyright notice,
this list of conditions and the following disclaimer in the documentation
and/or other materials provided with the distribution.
Neither the name of the author nor the names of its contributors may be
used to endorse or promote products derived from this software without
specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS OR CONTRIBUTORS BE
LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
POSSIBILITY OF SUCH DAMAGE.

=== Version History

* 0.4  Initial publication