Re: Timestamp Column.

On Thu, 30 Apr 1998 09:32:55 -0400, "Art S. Kagel" <kagel@bloomberg.com> wrote: >Actually we use the datatime/timestamp concept here to develop a unique >key for news stories and other such data that have no natural unique >key but for which a serial number is impractical. Yes, but to me this isn't a timestamp. It's two different words, and I believe they represent to different consepts. I think a datetime is simply a column that can contain a value representing an instance in time with a specified resolution. A timestamp however is allways something that represents relative time. That is one allways use a timestamp to be able to say that something occured before or after something else in time. True this can be implemented using a datetime column, but it's more common to use some kind of integer that is simply increased by 1 for every occurence of whatever you want to track. This something may be the updating of a single row in a table (the occurence to track beeing: Did an update occur to this row after I read it last?), the start of a backup (to track whether a page in the database was changed after the backup started) or any number of other things. It's rather important to keep ones concepts in order, so I would be very happy if someone could confirm or deny this distinction between a datetime and a timestamp. I know that what I explain above about a timestamp is the concept for which the word timestamp is most often used. What I would like to know is if this word does or should allways represent this concept, and no other, when we talk about databases. If this distinction is true I would also say that it's somewhat unfortunate that it's called a timestamp and not a versionstamp or something like that. Another better word might help in reducing the all to common missunderstanding that a timestamp is allways or commonly implemented via some kind of a datetime datatype. I am saying all this both to clarify things for myself, but also because this whole thread might have caused some confusion depending on what the original poster realy meant when he asked for the availability of timestamps in Informix databases. Nils Myklebust NM Data AS Norway E-mail: Nils.Myklebust@nmdata.com FAQ at: http://www.iiug.org/techinfo/faq/faq_top.html (Now with ODBC info under "Third party products".)