[boost] Re: boost::rtl / rel where can I get some more infos

10 Feb 2005

      Arkadiy Vertleyb wrote:
...
"Vinzenz Feenstra" <evilissimo@web.de> wrote
...
What exactly ist the motivation and the goal of rel/rtl ?
To implement an STL-compatible "relational table" container, that is
type-safe and allows fields of any built-in or user-defined type.
Naturally, once there is a container, operations are required.  Hence, the
relational algebra.
We think such library could become a good alternative to, for example, MS
Access, for light-weight applications.   Also, the possibility to perform
relational operations on objects might bring new and unexpected
possibilities.  As always with relational databases, the library is
particulary convenient and efficient when multiple views of the same data
are required and need to be kept in-sync.
HTH,
Arkadiy
Hmm, that sounds interessting.

I started thinking about doing some Policy Based, for a Database 
Frontend Library. And thought about using a STL-Container like interface
But this class will access a real database, like SQLite.

This what I am posting here is only an idea how it could be used:

------------------------------------------------------------------------

typedef  dbContainer<
                    // SQLite does not need any user/pw infos
                    dbDatabase ( "Company.db" ),
                    dbTable ( "Ware" ), // using table Ware
                    dbRow <  // defining the field of a row
                           dbValues <
                                     dbInt<
                                           "id" ,
                                           dbFieldOptions<
                                                          dbPrimaryKey

dbAutoIncrement
                                                         >
                                           >,
                                      dbText  < "name" > ,
                                      dbFloat < "price" >
                                     >
                         > , // end fields of a row definition
                    dbBackend < dbSQLite >  // use the SQLite Backend
                    >  WareTable;

typedef WareTable::row_type WT_Row;

WareTable wt_test;

wt_test.insert(WT_Row(dbNULLType, "Apple"  , "3.33" ));
wt_test.insert(WT_Row(dbNULLType, "Orange" , "2.13" ));
wt_test.insert(WT_Row(dbNULLType, "Peach"  , "4.57" ));
wt_test.insert(WT_Row(dbNULLType, "Plum"   , "7.49" ));

dbResIterator<WT_Row> results = wt_test.lookup(dbText<"name","Plum">);

while(results){
   while(results.columns)
      std::cout << *(results.columns++) << std::endl;
   ++results;
}

------------------------------------------------------------------------

However this is only an idea I have, where nothing of it is implemented 
or something.

I was asking myself if boost::rel/rtl will go in this direction or not.

A db- backend would be nice, wouldn't it?

Or a kind of SaveToDatabase ^^ xD

BR

Vinzenz