Re: DBD::File insert/update

On 06/08/10 11:42, Tim Bunce wrote:
> On Fri, Jun 04, 2010 at 04:12:18AM -0700, [email protected] wrote:
>>
>> +This modules uses hash interfaces of two column file databases. While
>> +none of supported SQL engines have a support for indeces, following
>
> s/indeces/indices/
>
>> +statements really do the same (even if they mean something completely
>> +different):
>> +
>> +  $sth->do( "insert into foo values (1, 'hello')" );
>> +
>> +  # this statement does ...
>> +  $sth->do( "update foo set v='world' where k=1" );
>> +  # ... the same as this statement
>> +  $sth->do( "insert into foo values (1, 'world')" );
>
> Is this really necessary? Can't we get duplicate inserts and
> updates of non-existent rows to behave in a sane manner?

The interface of the per-table API doesn't allow that :(
That's exactly the reason why I thought it's required to warn about that.
When I took over SQL::Statement and Tux got DBD::CSV, we talked each
other and discovered that an per-table API for indices is missing.

This is one goal I want to reach when developing SQL::Statement 2.0 - but
it will be a long road.

> The hash/DBM style databases should be modeled as two column tables
> with a unique constraint on the key column.

The table-API just knows: fetch_row, push_row, push_names and some
optimized routines to allow update/delete specific rows.

Jens