Re: [gnome-db] Partial Meta Store update.

[Bas Driessen <bas driessen xobas com>]

On Mon, 2009-07-20 at 10:52 +0200, Vivien Malerba wrote:
>     
>     
>     2009/7/20 Bas Driessen <bas driessen xobas com>
> >         On Sun, 2009-07-19 at 13:31 +0200, Vivien Malerba wrote:
> > >             
> > >             
> > >             2009/7/19 Bas Driessen <bas driessen xobas com>
> > > >                 Hello,
> > > >                 
> > > >                 Question regarding partial meta store update. I found that the following to update a single table does not appear to work:
> > > >                 
> > > >                         g_print ("\nPartial metastore update for table '%s'...\n", TABLE_NAME);
> > > >                         GdaMetaContext mcontext = {"_tables", 1, NULL, NULL};
> > > >                         mcontext.column_names = g_new (gchar *, 1);
> > > >                         mcontext.column_names[0] = "table_name";
> > > >                         mcontext.column_values = g_new (GValue *, 1);
> > > >                         g_value_set_string ((mcontext.column_values[0] = gda_value_new (G_TYPE_STRING)), TABLE_NAME);
> > > >                         if (!gda_connection_update_meta_store (connection, &mcontext, &error))
> > > >                                 return -1;
> > > >                 
> > > >                 After this, my meta store is NOT updated. 
> > > >             
> > >             
> > >             This may depend on the actual value of TABLE_NAME, specifically if it is a mix of upper and lower case, or if it's a reserved keyword. The proper way is:
> > >             tmp = gda_sql_identifier_quote (TABLE_NAME, cnc, NULL, TRUE, FALSE); // or with the last argument being TRUE, see the doc
> > >             g_value_set_string ((mcontext.column_values[0] = gda_value_new (G_TYPE_STRING)), tmp);
> > >             g_free (tmp);
> > >             
> > >             Note that this is brand new (just been sorted out) and will require the master or LIBGDA_4.0 branches up to date.
> > >              
> > > >                 
> > > >             
> > >         
> >     
> >         Thanks Vivien, but this unfortunately is not still not working. Let me explain my testing scenario and if I understand this the correct way.
> >         
> >         -1 I have a database with a table called "groups"
> >         -2 I run the gda_connection_update_meta_store to update the meta store.
> >         -3 I look into the meta store with sqlite3 and execute "select * from _tables". I can see the "groups" table in that list.
> >     
>     
>     So far so good:)
>      
> >         
> >         -4 I add a table called "parts"
> >         -5 I run the code above (with your modification) where the TABLE_NAME is set to "parts" (without quotes).
> >         -6 I execute "select * from _tables" and I expect to see the "parts" entry, but it is not there.
> >     
>     
>     It should be there...
>      
> >         
> >         -7 I execute the gda_connection_update_meta_store to do the full update.
> >         -8 I execute "select * from _tables" and I expect to see the "parts" entry and now it is there.
> >         
> >         My questions:
> >         
> >         -1 Is my understanding of how this mechanism should work correct?
> >     
>     
>     Ye, it is.
>      
> >         
> >         -2 Anything (obvious) that is not in the code above?
> >         -3 I use "gda_meta_store_new_with_file" to open my (sqlite3) meta store database. Is it possible that somehow it is mixing up the internal (memory) database with the external one?
> >     
>     
>     I don't think so, but I'd prefer to have some actual code to look at before I can say...
>     
>     If you send me a standlone program which shows the bug, I'll make the necessary corrections (either to Libgda or to your code).

Attached a small application that demonstrates the single table problem. Set up as follows:

(postgresql) database with 1 more tables
data source called "stocksql" (or change the connection name in the source).

The program performs the following steps:

-1 Open the connection
-2 Open the meta store
-3 Drop table "xparts" (if exists)
-4 Build complete meta store
-5 Create table "xparts"
-6 Update SINGLE table meta store.


After this open: sqlite3 /tmp/single.db

select * from _tables

There should be an entry for "xparts", but it is not there.

Is this enough input?

As a comment, I quickly put this together, so the error handling and program style is not the nicest :) Also I did not use DDL calls for drop table etc as that is not the focus anyway.

Thank you,
Bas.

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