Re: [gnome-db] libgda escape_value() and schema retreival

[Rodrigo Moya <rodrigo gnome-db org>]

On Tue, 2004-08-17 at 23:34 +0800, Alan Knowles wrote:
> Rodrigo- , thanks for looking at it/ addressing it.
> 
> Murray Cumming wrote:
> 
> >This seems to add a function like this:
> >
> >gboolean
> >gda_connection_escape_string (GdaConnection *cnc,
> >			      gchar *from,
> >			      const gchar *to,
> >			      unsigned long length)
> >
> >So,
> >  
> >
> 
> >1. Why do we need to provide the length of the "from" string? Surely, all
> >strings in libgda are null-terminated?
> >  
> >
> Sorry dont know libgda that well to comment..
> 
> >2. It seems to convert from "to" to "from". Isn't that a bit backwards?
> >  
> >
> Actually, it was a pretty straight copy from the original mysql_/pgsql_ 
> functions that did the same thing. - the only justification for keeping 
> that standard was probably that anyone who's familar with the API's 
> would pick up libgda a minute bit faster..
> 
> >3. Is this just for creating SQL-representations of text values? Surely
> >it's more useful to have a funciton to create a SQL representation of a
> >GValue, whatever type that GValue has.
> >  
> >
> I agree, That would be better, In reality though, it's only strings 
> AFAIK that need escaping, and may be locale specific on the database 
> (eg. BIG5 in a mysql db, has to watch out what it quotes..) so if it was 
> implemented as a Gda_connection_value_to_Sql(Gda_connection, 
> Gda_value,gchar) - only when the gda_value was a string, would the 
> function be called.
> 
> >4. Does this add the quotes, or do you need a big switch/case (switching
> >on the field type) block in the app for that?
> >  
> >
>  actually, only a few types varchar/char/text need escaping (which are 
> represented as a single type in gda? AFAIK), so it's not that huge a 
> switch/case.
> 
well, if we have the escape_value, apps would use it to generate the SQL
strings, so they would be calling the escape_value function for each
value they want to convert, so yeah, I guess we'll need a huge
switch/case in each provider's implementation of the escape_value
method.
-- 
Rodrigo Moya <rodrigo gnome-db org>