in reply to RFC : AJAX + DBI = DBIx::LiveGrid

Thanks for this.

I had a few problems using DBD::ODBC and MS SQL Server. With a table of 1000 rows:

What I found is the data grid displayed the first 70 rows repeatedly as you scrolled. I tracked this down to the SQL being run and then found SQL::Abstract::Limit says $order must be specified when $rows is specified. DBIx::LiveGrid only sets $order if you click on a column heading. I verified this with SQL::Abstract::Limit which produces the following incorrect SQL when $order is not specified:

SELECT * FROM ( SELECT TOP 10 * FROM ( SELECT TOP 30 f1, f2 FROM bench_char ) AS foo ) AS bar
and the following correct SQL when $order is specified:
SELECT * FROM ( SELECT TOP 10 * FROM ( SELECT TOP 30 f1, f2 FROM bench_char ORDER BY f1 ASC ) AS foo ORDER BY f1 DESC ) AS bar ORDER BY f1 ASC

I did a rough change to DBIx::LiveGrid to work around this:

sub query_database { my($self,$dbh,$table_name,$fields,$where,$order)=@_; my $rows = $self->get('ajax_page_size'); my $offset = $self->get('ajax_offset'); my $sort_dir = $self->get('ajax_sort_dir'); my $sort_col = $self->get('ajax_sort_col'); $sort_col = $self->clean_param('sort_col',$sort_col); my @porder = (); if ($sort_col) { @porder = ("$sort_col $sort_dir"); $order = \@porder; } require SQL::Abstract::Limit; my $abstract = SQL::Abstract::Limit->new( limit_dialect => $dbh ); my( $stmt, @bind ) = $abstract->select( $table_name , $fields , $where , $order , $rows , $offset );
and then changed livegrid.cgi:
my $dbh = DBI->connect("dbi:ODBC:test", "Martin_Evans", "easyso +ft", {RaiseError=>1,PrintError=>0}); my $table_name = "bench_char"; my @fields = qw/f1 f2/; my @order = qw/f1/; DBIx::LiveGrid->run( undef, $dbh, $table_name, \@fields, undef, \@orde +r );

I hope this helps.

BTW, I think there is a bug in IE 6.0.2800.1106 which means the row data is not updated every time when scrolling past the rowset points (70).

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Re^2: RFC : AJAX + DBI = DBIx::LiveGrid
by jZed (Prior) on Sep 16, 2005 at 14:49 UTC
    Thanks for spotting this and finding the right place to fix. I'll add a default sort-order on the first column but allow programmers to over-ride it.

    The Rico site forum has a lot of bug reports and fixes for browser scrolling bugs, I'd imagine they've seen the one you mention, but you might want to post it over there.