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# $Id: DBI.pm 6755 2006-08-06 21:21:03Z timbo $
# vim: ts=8:sw=4
#
# Copyright (c) 1994-2004  Tim Bunce  Ireland
...
# --------------------------------------------------------------------
# === OPTIONAL MINIMAL BASE CLASSES FOR DBI SUBCLASSES ===

# We only define default methods for harmless functions.
# We don't, for example, define a DBD::_::st::prepare()

{   package		# hide from PAUSE
	DBD::_::common; # ====== Common base class methods ======
    use strict;

    # methods common to all handle types:

    sub _not_impl {
	my ($h, $method) = @_;
	$h->trace_msg("Driver does not implement the $method method.\n");
	return;	# empty list / undef
    }

    # generic TIEHASH default methods:
    sub FIRSTKEY { }
    sub NEXTKEY  { }
    sub EXISTS   { defined($_[0]->FETCH($_[1])) } # XXX undef?
    sub CLEAR    { Carp::carp "Can't CLEAR $_[0] (DBI)" }
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