- From: Al Gilman <asgilman@access.digex.net>
- Date: Wed, 8 Oct 1997 00:40:13 -0400 (EDT)
- To: w3c-wai-hc@w3.org (HC team)
to follow up on what Dave Raggett said: > > > One is that, while it is well and good to talk about how one > > would do a full readout of a table under different sub-class > > hypotheses, that interactive browsing of the table is more > > critical to successful use by speech users. > > Absolutely. I feel it is critical to enable browsing, including > the ability to suppress and expand levels of detail. > When you say "suppress levels of detail" I hear you assuming that there is a semantically valid way to form a composite or summary for some set or rows or columns. That requires a special kind of table to start with. Maybe you mean what I have been thinking about in terms of the construction of reduced tables by hiding selected rows and columns. In the meantime, I still haven't got closed-loop confirmation that you grok what I am calling "keys." I would like to know if - you have got the concept but don't think it's important enough to waste an attribute and default rule on, or - I haven't make the concept clear enough yet. One way to explain the "keys" concept is the idea that keys are [for example columns] that you can't suppress without destroying the validity of the data. These are necessary preconditions for the data in some related cell to be valid. You can suppress some of the columns in a table, but if you have a multi-column set of keys required to isolate a[n entity or] unique case, then hiding one of the key columns results in an invalid relation. Another way to explain the concept is the idea that most tables people actually use are not just relations but are actually tabulations of _functions_. In terms of the gut appreciation of the table, the reader and writer know which dimensions are inputs and which are outputs. The inputs are the keys. Knowing which dimensions are the inputs, and span the domain of the function, is essential to interpreting the data in the cells. Is any of this getting across? I am not sure that you are thinking about the simplest form of table, one which is just a list of records with a sufficient key in column 1, and other attributes of the entities keyed by column 1 presented in further columns. In this case, the minimal reduced table that goes with each cell is cells (A1) (X1) (An) (Xn) Here X and n are arbitrary columns and rows (>A and >1), respectively. The axes attribute for cell Xn is just the TH at X1, and it can be made so efficiently by putting a scope indication of "column" on the X1 cell. For that matter, the default in absence of any overt indication is probably that "axes" defaults to TH cells above the TD cell, so we probably don't need any markup in this case. [Maybe this is just true for the row-major or rows-are-the-dominant-substructure classes of tables.] I don't see how the AXES/AXIS markup would tell me that I need to read the data in An together with Xn to make Xn valid. And the data that are necessary to establish the validity of the data in column X are not always just what is in column A. It may take several of the other columns [or more generally, other cells] to completely describe the conditions under which the data in cell Xn are valid. The minimum reduced table includes the current cell and any other cells that are axes _or keys_ for that cell, together with [abbr's for] the axes of the keys. Does the AXIS/AXES attribute set convey what I am calling key relationships and I am just missing it? -- Al
Received on Wednesday, 8 October 1997 00:40:31 UTC