Re: [gnome-db] gda_connection_create_table() equivalent.

["Vivien Malerba" <vmalerba gmail com>]

On 8/28/06, Bas Driessen <bas driessen xobas com> wrote:
>  On Mon, 2006-08-28 at 14:03 +0200, Rodrigo Moya wrote:
>
>  On Sun, 2006-08-27 at 11:00 +0200, Vivien Malerba wrote:
> > On 8/27/06, Bas Driessen <bas driessen xobas com> wrote:
> > >
> > > Hello,
> > >
> > > I noticed that functions like gda_connection_create_table() have been
> > > removed recently. This now should go through a new GdaServerOperation.
> Is it
> > > possible to give an example of how I would create a table now? I used
> > > function calls like this:
> > >
> > > gda_connection_create_table(connection, table_name,
> > > columns, NULL)
> > >
> > > What would the equivalent be with this new GdaServerOperation? Any
> > > clues/examples?
> >
> > Example to create a table. The idea is to ask a provider for a
> > GdaServerOperation for a given operation to perform, then set the data
> > in the GdaServerOperation (here from an XML string), and the ask the
> > provider to execute the operation. The parameters to be set for each
> > kind of operation is provider-dependant, but there is a common set
> > mentionned in the libgda doc (such as table name and columns to create
> > a table).
> >
> > For more examples, have a look at src/util.c and src/ws-tables.c in
> > mergeant. You can use libgnomedb's GnomeDbServerOperation widget to
> > have a GUI to enter the necessary parameters for a given
> > GdaServerOperation.
> >
> > GdaServerOperation *op;
> > GError *error = NULL;
> >
> > op = gda_server_provider_create_operation (prov, cnc,
> > GDA_SERVER_OPERATION_CREATE_TABLE, NULL, &error);
> > if (!op) {
> > /* error */
> > }
> > else {
> > /* we have to set the table parameters */
> > const gchar *params = "
> > <serv_op_data>
> > <op_data
> path="/TABLE_DEF_P/TABLE_NAME">testtable</op_data>
> > <op_data path="/FIELDS_A">
> > <gda_array_data>
> > <gda_array_row>
> > <gda_array_value colid="COLUMN_NAME">id</gda_array_value>
> > <gda_array_value
> colid="COLUMN_TYPE">int</gda_array_value>
> > </gda_array_row>
> > </gda_array_data>
> > </op_data>
> > </serv_op_data>"
> >
> > doc = xmlParseMemory (params, -1);
> > if (!gda_server_operation_load_data_from_xml (op,
> > xmlDocGetRootElement (doc), &error)) {
> > /* error */
> > }
> > else {
> > gda_server_provider_perform_operation (prov, cnc, op,
> &error) {
> > /* error */
> > }
> > else {
> > /* ok, table created */
> > }
> > }
> > xmlFreeDoc (doc);
> > g_object_unref (op);
> > }
> >
> > Hope this helps,
> >
> it would be nice to have in the API convenience functions that do all
> this work for common operations, like creating a table. How do you see
> it?
>
>
>  Agreed. Example of a simple drop table:
>
>  Old situation only 1 line:
>
>  status = gda_connection_drop_table(connection,
> extTableName);
>
>
>  New situation 31 lines (not tested yet, but should at least be close)
>
>                  prov =
> gda_connection_get_provider_obj(connection);
>                  op = gda_server_provider_create_operation
> (prov, connection, GDA_SERVER_OPERATION_DROP_TABLE, NULL,
> &error);
>
>                  if (!op)
>                  {
>                          /* error */
>                  }
>                  else
>                  {
>
>                          /* we have to set the table parameters */
>                          docOp = xmlNewDoc((const xmlChar *)XML_VERSION);
>                          docOp->children = xmlNewDocNode(docOp, NULL, (const
> xmlChar *)"serv_op_data", NULL);
>                          curOp = xmlDocGetRootElement(docOp);
>                          curOp = xmlNewTextChild (curOp, NULL, (const
> xmlChar *)"op_data", (const xmlChar *)extTableName);
>                          xmlNewProp (curOp, (const xmlChar *)"path", (const
> xmlChar *)"/TABLE_DESC_P/TABLE_NAME");
>
>                          if
> (!gda_server_operation_load_data_from_xml (op,
> xmlDocGetRootElement (docOp), &error))
>                          {
>                                  /* error */
>                          }
>                          else
>                          {
>
> if(!gda_server_provider_perform_operation (prov,
> connection, op, &error))
>                                  {
>                                          /* error */
>                                  }
>                          }
>                          xmlFreeDoc (docOp);
>                          g_object_unref (op);
>                  }

All right for that example, now take the create table example and the
new API will have less lines of code (with the new API create table
allows to specify PK, FK, column and global table constraints as well
as table inheritance). I can't even imagine the API required to
express all that!

Also the API regarding GdaServerOperation's information setting can be
much improved (and will when I have the time) to avoid having to use
XML.

Cheers,

Vivien