[wsf-c-dev] Embedding Axis2 to MySQL

[Milinda Lakmal]

Hi,

As described in the MySQL documentation under "Extending MySQL" 
(http://dev.mysql.com/doc/refman/5.1/en/extending-mysql.html), there are 
two ways to ways to add new functions to MySQL:

    *

      We can add functions through user-define function (UDF) interface.
      User defined functions are compiled as object files and then added
      to and remove dynamically using CREATE FUNCTION and DROP FUNCTION
      statements.

    *

      Or we can add functions as native (built-in) MySQL functions.
      Native functions are compiled into the mysqld server and become
      availabl on a permanent basis.

If we write UDFs, we must install object files in addition to the server 
itself. If we compile our functions to the server, we don't need to do that.
But in the case of Native functions we modify a source distribution. We 
can add UDFs to a binary MySQL distribution. If we use the Native 
function method we have to repeat modifications to the source each time 
we upgrade the MySQL.  We can continue to use previously installed UDFs, 
unless you upgrade to a newer version for which the UDF interface changed.
So, I think in our case UDFs are better.
We can't use MySQL plugin API, because current version only support 
full-text parser plugins only.
I also looked at the what parthipan has done. He has written a UDF which 
is a client for add function in the Calculator service. I think we have 
to develop UDFs that support accessing any web service. So when giving a 
function to access any web service via MySQL functions, I think we have 
to decide parameters given to that function and return value from the 
function. Currently MySQL only support function STRING, INTEGER and REAL 
functions.

STRING function means, function that return MySQL STRING. (same for 
other types)

-------------------------
| SQL Type   | C/C++ Type |
-------------------------
| STRING     | char *     |
| INTEGER    | long long  |
| REAL       | double     |
---------------------------

If you have any suggestions regarding embedding Axis2 to MySQL, please 
send it to the mailing list.

Thanks
Milinda