On 2006-10-06, Nicola Musatti <Nicola.Musatti@gmail.com> wrote:
Steve Hutton <shutton <at> featurecomplete.com> writes: [...]
I think it would be good practice to keep both queries and their related TypeConversions in the same header file. But of course even this isn't enough to ensure queries don't break - the database itself can always change But using select * is another precaution that gives some added protection from database changes.
This is the reason why it's important that libraries such as SOCI provide a dynamic interface to query composition and navigable, explicitly meta-represented result sets.
Indeed, SOCI supports dynamic querying, i.e. where column names are unknown at compile time: http://soci.sourceforge.net/doc/exchange.html#dynamic
Those who want (or, rather, can afford) type safety should build it above the dynamic interface.
Well SOCI lets you do that if you really want to, but it supports static binding directly...
For them code generation is an effective solution, especially considering that parsing SQL DDL (as opposed to C++ class definitions) is rather easy.
Parsing DDL shouldn't be necessary for end users. SOCI::ColumnProperties provides basic access to column meta data, and (most?) db backends allow (db-specific) retrival of more detailed meta data via sql itself. Steve