On Mon, Oct 27, 2003 at 07:37:18AM -0800, Dean Arnold wrote:
> >
> > Google for my previous posts about a preparse() method for my
> > thinking on handling client-side parsing for placeholders and
> > SQL translations. (This work hasn't got very far and if it doesn't
> > soon I'll be asking for volunteers with Parse::RecDescent experience
> > to step forward.)
>
> Is the purpose of this solely for placeholders, or is this an attempt
> at a universal SQL syntax (ala ODBC's conformance levels) ?
Somewhere in between.
> I assume that using existing platform-specific SQL will still be
> permitted (wo/ lots of ANSI escape clauses) ?
Of course.
> (I'd hate to see DBI turn into a LCD-only lib)
Likewise.
> > For the binding I really don't want to add new methods, so the
> > driver would need to be changed to recognise a bind_param to a named
> > placeholder and get the corresponding set of placeholder index
> > values to use.
> >
> > Now a question to all: which database servers, other than Oracle,
> > support named placeholders and what syntax do they use?
>
> Teradata supports named placeholders. The syntax is
> :NAME, ie, SELECT * FROM TABLE WHERE COL1 = :col1;
So it matches Oracle syntax. Does DBD::Teradata allow
$sth->bind_param(":col1", $foo);
like DBD::Oracle? If not, could it?
> BTW: I don't see anything in DBI 1.38 that checks for
> numeric parameter ID in bind_param() (tho bind_param_array() does),
> so is it safe to assume individual drivers *could* just implement such
> (non-portable) support on their own
Yes. DBD::Oracle always has.
> (excluding array-binding support, and the "default"
> binding via execute()/execute_array()). Which also raises the issue of how
> the default bindings would map to named PHs (perhaps a simple arrayref
> of the names supplied as an attribute ?)
No. The only thing I'd be happy with is what DBD::Oracle does.
Use implicit placeholder names for the value so
$sth->execute($foo, $bar);
is the same as
$sth->bind_param(":p1", $foo)
$sth->bind_param(":p2", $bar)
$sth->execute();
Interestingly, the way it does that is to translate 'normal'
placeholders into :p1, :p2 etc when the SQL is prepared.
Then bind_param(1, ...) is treated as bind_param(":p1",...)
which then means the Driver.xst for execute() "just works".
Tim.
