Re: [gnome-db] Re: GRAND MASTER PLAN

[Dru <andru treshna com>]

> A simple example, in C++ this time.
>
> Let us say we have a C++ object:
>
> class MeinBlau {
> 	public:
> 		char * get_blaupunkt (void);
> 		void set_blaupunkt (char *);
> 	private:
> 		double blaupunkt;
> };
>
> Let us say we have a "Grand Master DB Interface".  I want to 
> prostrate myself before the Grand Master and say:
>
> "Oh grand master, in your infinite wisdom, there is an SQL database
> somewhere, and it has a table with a record with UUID=123.  Please
> copy that SQL database record into my object MeinBlau."
>
> I want to do the above with one subroutine call:
> grand_master_copy_from_sql (MeinBlau *myobj, char *Use_the_sql_driver);
>
> There is an assumption that at some earlier time, I made declarative
> statements that explained which sql table fields get hooked up
> to get_/set_blaupunkt.
>
> I want to go on:
>
> "Oh grand master, in your infinite wisdom, I know that there is
> another SQL user out there who is editing and modfying this database.
> Please always make sure that my object is kept in sync with that
> database.  Please provide me with an event or a callback or means
> of polling such changes made by others."
>
> "Oh, and by the way, when I change *my* instance of this object,
> please notify these distant, remote, other users on the other 
> side of the planet that my copy now contains the most recent 
> data, and please put that data back into the sql db for me."
>
> ------------
> Now, because the grand master has the buddha-nature,  it can satisfy
> these requests if I substitute the words "gtk widget" for "sql database"
> in the above prostrations.  Or the words "abiword document". The
> word "sql" simply helps identify the data source.
>
> -----------
> Now in fact, I have many instances of class MeinBlau, and I need to
> perform a set of operations on it.  I want to be able to say:
>
> "Oh grand master, I have many pointers to many instances of MienBlau 
> in my bag, but I am blind and cannot find the ones I need.  Can you
> help me find those with blau>2.5 ? Oh, and grandmaster, I know that
> not all such instances are in my bag.  Some are very far away, in 
> a remote database.  So can you please search over those too, and 
> hand me pointers to those as well? (oh yeah, and keep them in sync 
> too)"


I knew there was majic involved.

But you can make it more complex.

grand_master_copy_from_sql (&someobj, "select ae,aa.e from ae,aa where 
ae.c>'3' and ae.b=aa.b");

and then for extra trickness
grand_master_copy_from_myotherobj (&myobj, another_unrelatedobj);
So you can make MeinPad's from MeinBlau's.