On 16 Apr 2012, at 10:31pm, Peter Aronson <[email protected]> wrote:
> You might want to look at the book Temporal Data and the Relational Model by > Date, Darwin and Lorentzos, which goes into the subject in fairly great > detail. > There are subtleties. Doctor Darwen teaches this as a course. You might like to read the free detailed course notes here: <http://www.dcs.warwick.ac.uk/~hugh/TTM/TemporalData.Warwick.pdf> Unfortunately he uses terms aimed at an academic mathematical understanding of attributes (relvars), which are difficult to understand if you're just a programmer at the rock face. What it comes down to is that if the only data you have is the result of SQL commands you don't have enough data to understand the facts implicit in the contents of your tables. I urge again the different approach I mentioned earlier. Forget keeping the data, and instead keep the commands used to change the data. That way, instead of keeping the /results/ of your SQL commands, you're keeping the commands yourself, which is rawer (more raw ?) data, and therefore more faithful to what you know, rather than what you're trying to deduce. Whether you are keeping copies of the rows in the table, or timestamping SQL commands, I suggest that for SQLite your timestamps should be unixepoch stored as a REAL rather than a text expression of seconds. Simon. _______________________________________________ sqlite-users mailing list [email protected] http://sqlite.org:8080/cgi-bin/mailman/listinfo/sqlite-users
