You're much too nice.
Rachel Carmichael To: Multiple recipients of list ORACLE-L <[EMAIL PROTECTED]> <wisernet100 cc: @yahoo.com> Subject: Re: How do you genrate primary keys? Sent by: ml-errors 11/05/2003 09:44 AM Please respond to ORACLE-L It was a compromise... since they had already written their code, I put in the triggers so that it was transparent to them that the "key" they were generating was not being used. I had to give them something, since I was really trying hard NOT to say "I told you so!" --- Yong Huang <[EMAIL PROTECTED]> wrote: > Rachel, > > That's a good case to remember. Java programmers (or architects) > sometimes miss > those little things. > > I would ask why you used triggers to populate the PK field instead of > saying > INSERT ... MYSEQUENCE.NEXT_VAL in the code, or even INSERT ... SELECT > ROWNUM > (or ROWNUM+somefixedvalue). Wouldn't these perform better? > > Yong Huang > > --- Rachel Carmichael <[EMAIL PROTECTED]> wrote: > > At one site I worked at, the programmers insisted on using Java > > milliseconds as the primary key -- so that they wouldn't have to > hit > > the database twice (once to get the sequence number, once to insert > the > > row). They swore up, down and six ways from Sunday that there could > > never, ever, EVER be a collision. > > > > After we had collisions in development, we switched to sequences > (one > > per table), with a trigger to populate the field on insert so that > they > > wouldn't have to make the second round-trip. > > > > > > --- Jonathan Gennick <[EMAIL PROTECTED]> wrote: > > > The recent article that mentioned sequences got me to > > > thinking. I might pitch a more detailed article on sequences > > > to Builder.com. But a more interesting article might be one > > > that explored various ways to automatically generate primary > > > keys. So, in the name of research, let me throw out the > > > following questions: > > > > > > What mechanisms have you used to generate primary keys? > > > Which ones worked well, and why? Which mechanisms worked > > > poorly? > > > > > > I've run up against the following approaches: > > > > > > * Hit a table that keeps a counter. This is the "roll your > > > own sequence method". The one time I recall encountering > > > this approach, I helped convert it over to using stored > > > sequences. This was because of concurrency problems: with > > > careful timing, two users could end up with the same ID > > > number for different records. Is there ever a case when this > > > roll-your-own approach makes sense, and is workable? > > > > > > * Stored sequences. I worked on one app that used a separate > > > sequence for each automatically generated primary key. I > > > worked on another app, a smaller one, that used the same > > > sequence for more than one table. The only issue that I > > > recall is that sometimes numbers would be skipped. But end > > > users really didn't care, or even notice. > > > > > > * The SYS_GUID approach. I've never used SYS_GUID as a > > > primary key generator. I wonder, was that Oracle's > > > motivation for creating the function? Has anyone used it for > > > primary keys in a production app? What's the real reason > > > Oracle created this function? > > > > > > * Similar to SYS_GUID, I once worked on an obituary-tracking > > > application that built up a primary key from, as best I can > > > recall now: date of death, part of surname, part of first > > > name, and a sequence number used only to resolve collisions, > > > of which there were few. The approached worked well, > > > actually, because whatever fields we munged together to > > > generate a primary key gave us a unique key the vast > > > majority of the time. > > > > > > The SYS_GUID approach is interesting, but if you need an ID > > > number that users will see, and that users might type in > > > themselves (e.g. social security number), is SYS_GUID really > > > all that viable? > > > > > > Best regards, > > > > > > Jonathan Gennick --- Brighten the corner where you are > > > http://Gennick.com * 906.387.1698 * mailto:[EMAIL PROTECTED] > > > > > > Join the Oracle-article list and receive one > > > article on Oracle technologies per month by > > > email. To join, visit > > > http://four.pairlist.net/mailman/listinfo/oracle-article, > > > or send email to [EMAIL PROTECTED] and > > > include the word "subscribe" in either the subject or body. > > > > > > -- > > > Please see the official ORACLE-L FAQ: http://www.orafaq.net > > > -- > > > Author: Jonathan Gennick > > > INET: [EMAIL PROTECTED] > > > > > > Fat City Network Services -- 858-538-5051 > http://www.fatcity.com > > > San Diego, California -- Mailing list and web hosting > services > > > > --------------------------------------------------------------------- > > > To REMOVE yourself from this mailing list, send an E-Mail message > > > to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and > in > > > the message BODY, include a line containing: UNSUB ORACLE-L > > > (or the name of mailing list you want to be removed from). You > may > > > also send the HELP command for other information (like > subscribing). > > > > > > __________________________________ > > Do you Yahoo!? > > Protect your identity with Yahoo! Mail AddressGuard > > http://antispam.yahoo.com/whatsnewfree > > -- > > Please see the official ORACLE-L FAQ: http://www.orafaq.net > > -- > > Author: Rachel Carmichael > > INET: [EMAIL PROTECTED] > > > > Fat City Network Services -- 858-538-5051 http://www.fatcity.com > > San Diego, California -- Mailing list and web hosting > services > > > --------------------------------------------------------------------- > > To REMOVE yourself from this mailing list, send an E-Mail message > > to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in > > the message BODY, include a line containing: UNSUB ORACLE-L > > (or the name of mailing list you want to be removed from). 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Mail AddressGuard http://antispam.yahoo.com/whatsnewfree -- Please see the official ORACLE-L FAQ: http://www.orafaq.net -- Author: Rachel Carmichael INET: [EMAIL PROTECTED] Fat City Network Services -- 858-538-5051 http://www.fatcity.com San Diego, California -- Mailing list and web hosting services --------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing). -- Please see the official ORACLE-L FAQ: http://www.orafaq.net -- Author: Thomas Day INET: [EMAIL PROTECTED] Fat City Network Services -- 858-538-5051 http://www.fatcity.com San Diego, California -- Mailing list and web hosting services --------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB ORACLE-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).