Re: [boost] [relational] Relational Model Library

From: Calum Grant (calum_at_[hidden])
Date: 2005-09-27 17:05:14

> -----Original Message-----

> [mailto:boost-bounces_at_[hidden]] On Behalf Of Larry Evans
> > Is there any interest in providing relational containers in Boost?  
> > Are there any features/improvements you can suggest for RML?
> http://visula.org/relational/implementation.html contains:
> 
>    The reason this has to be a macro is because it needs to work with
>    names, not just types.  It was felt that the benefits of 
> being able to
>    write customer.name or customers.name instead of 
> column<1>(customers)
>    or col<1,1>() outweighs the inherent disadvantages of 
> using a macro.
> 
> why not use an enumerator:
> 
>     column<name>(customers)
> 
> instead of a number:
> 
>     column<1>(customers)
> 
> ?  Would this eliminate the macro need?  

An early RML did use tuples indexed in the way you describe.  I did use
enums - writing magic numbers is very bad for readibility and
maintainability.  Personally I prefer to read

        customers.name

instead of 

        column<name>(customers)

There is also a big problem with enums - being able to associate the
correct enum with the correct type.  I.e. the "name" column may be 2 for
customers, and 3 for products.  So you really need
column<customer_name>(customers) and column<product_name>(product).

Calum