Re: Genealogical evidence and data model

Tim Powys-Lybbe wrote:
> In message of 3 Feb, Dennis Lee Bieber <wlfraed@[EMAIL PROTECTED]
> wrote:
> 
> <snip>
> 
>> 	But do you have the same meaning I associate with "flat file", or
>> could you be meaning a "heap file". To me, a "flat file" is one in
which
>> all records share the same structural layout, whereas a "heap file",
>> while record oriented, does not mandate each record looks similar to
the
>> previous or next. GEDCOM files can be considered a form of flat file if
>> you look at it from the view of
>>
>> data-level	data-key	associated data values
>>
>> where data-key identifies what type of data follows on the line.
> 
> This is completely in contrast to the meaning of 'flat file' when I was
> working with mainframe data managers some fifteen years ago.  Then a
> flat file was one with no structure like GEDCOM and which could be read
> easily by a text editor.  A relational database was constructed from
flat
> files, each of which was ****ted into a suitably defined table; though
> this required that each column in the flat file was used for a defined
> data type only.  Thus comma separated variable (CSV) and tab separated
> variable (TSV) files are both flat files.
> 
> GEDCOM on the other hand needs an extensive program to disentangle it
> and to communicate the data to a casual reader.  The fact that you can
> read GEDCOM in a text editor, though, does not make it into a flat file.
> 
> On a related topic, several genealogy programs use the GEDCOM structure
> as their input and output media.  I wonder if the keep the data
> unaltered for processing or if they convert it to a different internal
> structure for processing.  If the latter, I wonder what those structures
> are?  
> 

try reading an FTM file with a text editor

Hugh W