Re: [gnome-db] Meta Store issue with MySQL.

On Thu, 2009-07-30 at 16:17 +0200, Vivien Malerba wrote:

> 
> 
> 
> 2009/7/30 Bas Driessen <[email protected]>
> 
>         
>         > 2009/7/30 Bas Driessen <[email protected]>
>         >
>         >>  Hello,
>         >>
>         >> My database is in MySQL. When I run the following command
>         to rebuild the
>         >> MetaStore (which lives in a sqlite3 database):
>         >>
>         >> gda_connection_update_meta_store(connection, NULL, &error)
>         >>
>         >> I get the following error/warning:
>         >>
>         >> ** (process:22406): WARNING **: (+5): Wrong Holder value
>         type, expected
>         >> type 'boolean' when value's type is 'string' (Provider
>         ThreadWrapper)
>         >>
>         >>
>         >> and the MySQL table information is not in the MetaStore. In
>         fact if I
>         >> do:
>         >>
>         >> select * from _tables;
>         >>
>         >> nothing shows up.
>         >>
>         >> Anyone else having this problem?
>         >>
>         >
>         > The reason for this error is that a SELECT statement
>         internally run by the
>         > MySQL provider to get meta data returned a column of type
>         string instead
>         > to
>         > a boolean. To solve this, the correction consists in
>         locating the faulty
>         > SELECT, and use
>         gda_connection_statement_execute_select_full() with an
>         > array
>         > of expected types for the columns instead of
>         > gda_connection_statement_execute_select(). This is already
>         done at several
>         > places in gda-mysql-meta.c.
>         >
>         > If you want to try to correct it, and if you are in the
>         master branch, you
>         > can use the definitions in
>         > libgda/providers-support/gda-meta-column-types.h
>         > (which is dynamically generated).
>         >
>         > Otherwise, I'd need to have more information to correct the
>         problem
>         > myself.
>         
>         
>         
>         OK, I will try to locate and correct the issue in libgda. Just
>         wanted to
>         have confirmed first that this is an issue in libgda and not
>         in my setup.
>         
> 
> To help you, you can uncomment the line 2324 of the gda-meta-store.c
> file, so you'll get debug info about all the results the provider is
> returning for the meta store.
> 


Thanks Vivien ... I tried, but it is difficult to get a handle on the
flow of code etc. Therefore, I created a small reproducible. Probably
faster to get to the core of this issue :)

Steps in the little program below as follows:

-1 Open connection to MySQL. My data source is called "mystock".
-2 Open a data store in sqlite format.
-3 Rebuild the complete store. This will fail. Even if there are no base
tables, there should always be something in the _tables for instance.
There is nothing there, which probably makes sense as a rollback is
triggered if there is a problem.

To check the result:

sqlite3 /tmp/mysql_meta.db

select * from _tables;

Nothing returned.

Can you please test if this is failing in your environment too? The code
is as follows:

==============
#include <libgda/libgda.h>

int
main (int argc, char *argv[])
{
        GdaConnection* connection;
        GError* error = NULL;
        GdaMetaStore *store;

        gda_init();
        error = NULL;

        /* open connection */
        printf("Start.\n");
        printf("Open connection.\n");
        connection = gda_connection_open_from_dsn ("mystock", NULL,
GDA_CONNECTION_OPTIONS_NONE, &error);
        if (!connection)
        {
                fprintf (stderr, "%s\n", error->message);
                return -1;
        }

        /* Open Meta Store */
        printf("Open Meta Store.\n");
        store = gda_meta_store_new_with_file("/tmp/mysql_meta.db");
        g_object_set(G_OBJECT(connection), "meta-store", store, NULL);
        if (!store)
        {
                printf("Can not open store.\n");
                return -1;
        }

        /* Build Complete store */
        printf("Build complete store.\n");
        if (!gda_connection_update_meta_store(connection, NULL, &error))
        {
                fprintf (stderr, "%s\n", error->message);
                return -1;
        }

        /* The End */
        printf("End.\n");
        return 0;
}

==============

Thanks,
Bas.

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