+=item count [ WHERE ]
+
+Convenience method for the common case of "SELECT COUNT(*) FROM table",
+with optional WHERE. Must be called as method on a class with an
+associated table.
+
+=cut
+
+sub count {
+ my($self, $where) = (shift, shift);
+ my $table = $self->table or die 'count called on object of class '.ref($self);
+ my $sql = "SELECT COUNT(*) FROM $table";
+ $sql .= " WHERE $where" if $where;
+ $self->scalar_sql($sql);
+}
+