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RE: Data and layout tables: examples

From: Michele Diodati <michele@diodati.org>
Date: Tue, 3 Jun 2003 18:54:21 +0200
To: <w3c-wai-gl@w3.org>
Message-ID: <004c01c329f0$cc790940$0b00a8c0@oligo>

This is a little contribution to point out the difference between data
and layout tables.

A data table is a table in which you can't alter the position of a cell
in a column or in a row without altering data consistency. For example,
if you have a two column table in which the first column contains
people's names and the second column contains their telephone numbers,
you can't move the content of a cell up or down in the second column
without destroying the relationship between at least two names and two
numbers. The same rule applies to data headers: in the foregoing example
I can't invert "names" header with "telephone numbers" header at the top
of the table without destroying consistency between headers and data in
the table.

On the contrary, a layout table is a table in which you *can* modify the
position of a cell in a column or in a row without altering data
consistency. Doing so, you only alter the appearance of the page. For
example, if you have a three column/one row layout table, in which the
first column contains the site menu, the second column contains a list
of abstracts from the last articles published on the site and the third
column contains some links to other sites, you can freely invert the
position of the three cells without altering data consistency: the list
of abstracts will remain meaningful wether you put it on the left, on
the center or on the right.

Perhaps you may summarize this difference saying that a layout table is
a table in which you can't use properly CAPTION and TH elements.

All the best,
Michele Diodati
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http://www.diodati.org
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Received on Tuesday, 3 June 2003 12:54:31 GMT

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