Re: RFC: [b]lob_read in DBD::ODBC and other DBD differences

On Tue, Jul 20, 2010 at 09:46:42PM +0100, Martin J. Evans wrote:
> [...]
> 
> As a result of the above, I don't see any way of supporting the existing
> blob_read in DBI and as it is undocumented anyway and no DBDs seem to
> use it

Feel free to mark it deprecated in the DBI docs..

> I've put a test implementation together as:
> 
> odbc_lob_read(sth, colno, buf, length, \%attrs)
> 
> where \%attrs can contain TYPE => SQL_type.

> I appreciate this RFC is quite long and I'm guessing few people will get
> to the end. Increasingly, I'm working with several DBDs and the
> differences between them (beyond SQL differences) is proving VERY
> frustrating. It would be nice to try and sort out lob reading and whilst
> I'm on a roll, SQLMoreResults/more_results, last_insert_id, lob_write,
> binding with a specific type etc  but I guess since some of these have
> been covered before and we didn't get too far in the past that perhaps
> there is not a lot of interest in it. I'd like to fit DBD::ODBC with
> DBI's blob_read but I don't think it works for DBD::ODBC as it stands
> and I note other DBDs have provided their own lob reading methods
> substantially different so I'm guessing they found that too.

I encourage driver authors to implement a 'natural' private API first
before working together to agree on a common API for the DBI.
(The blob_read API is an example of what happens when the DBI specifies
things before drivers support them.)

> With Perl 6 perhaps on the horizon and Tim's current interest in JDBC I
> think we are well advised to sort some of this out in Perl 5 first. It
> makes little difference to me right now as I'll implement what I need
> now and move on but I'm prepared to work to a DBI interface for the
> common goal. Some of this is not going to go away - you only have to
> watch perl monks to see the frustration with last_insert_id, lob
> reading, binding columns with types etc across DBDs to know this is
> proving troublesome for the average user.

Tim.