Re: Antwort: Re: Why Heap Tables doesn´t support auto increment ?colums
So sprach Gerhard Schmidt am Thu, Mar 01, 2001 at 04:02:54PM +0100: Besides the fakt tha this ID not unique. There ist the Problem that the ID you proposed ist an String ID and strings als Index are the Well, but he could make a two column primary key, where the first is the timestamp, and the second an unsigned int holding the ip, if the ip is first transformed from the usual dotted notation (1.2.3.4) to the "raw" number (which would be 4+3*256+2*256*256+1*256*256*256 in this case - 16909060 ). Thus would give a timestamp + integer key, which is fast to index. The question still is. Why are auto_increment columns are not supported True. Alexander Skwar -- How to quote: http://learn.to/quote (german) http://quote.6x.to (english) Homepage: http://www.digitalprojects.com | http://www.iso-top.de iso-top.de - Die guenstige Art an Linux Distributionen zu kommen Uptime: 15 hours 19 minutes - Before posting, please check: http://www.mysql.com/manual.php (the manual) http://lists.mysql.com/ (the list archive) To request this thread, e-mail [EMAIL PROTECTED] To unsubscribe, e-mail [EMAIL PROTECTED] Trouble unsubscribing? Try: http://lists.mysql.com/php/unsubscribe.php
Re: Why Heap Tables doesn´t support auto increment colums
Why not use a timestamp column to guarentee the order in which rows get inserted into the table? You can then order on the timestamp column. Gerhard Schmidt wrote: --d6Gm4EdcadzBjdND Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Hi,=20 I wounder why there is no support for Auto_increment fields in Heap tables. I know there is a problem with the uniqueness of this columns=20 but some times the uniqueness of the column is only needes as long=20 as the heap table exists.=20 I=B4m currently working on system for Managing http Session and would like= =20 to use a heap table for storing the session information. Session=20 information is only of temporary intrest. But still I need an unique=20 ID for reference with some other Tabels storing dtaa for the session.=20 All these tables are Heap tables. So there is no Probelem if the ID=20 generated by the auto_increment column is not unique when the Database server is restarted.=20 - Before posting, please check: http://www.mysql.com/manual.php (the manual) http://lists.mysql.com/ (the list archive) To request this thread, e-mail [EMAIL PROTECTED] To unsubscribe, e-mail [EMAIL PROTECTED] Trouble unsubscribing? Try: http://lists.mysql.com/php/unsubscribe.php
Re: Antwort: Re: Why Heap Tables doesn´t support auto increment ?colums
On Thu, Mar 01, 2001 at 02:37:30PM +0100, Entryon Corp., Chief Technical Officer - P. Hasenfratz wrote: Why not use a timestamp column to guarentee the order in which rows get inserted into the table? You can then order on the timestamp column. Hmm, timestamp, ie. seconds as finest resolution, might be to broad depending on the hits his site will get - imagine that 2+ users access the site in the same second, then you won't be able to distinguish them, will you? What's if you combine a timestamp with the client's IP address? for example: 5/6/2001 IP : 212.33.69.2 = clientstamp will be 05.06.2001-212.033.069.002 Besides the fakt tha this ID not unique. There ist the Problem that the ID you proposed ist an String ID and strings als Index are the Major Preformance killer on Databases. Wie kann calculate an intager from the two information. totaly loosing the Uniqueness. The question still is. Why are auto_increment columns are not supported fuer Heap Tables. SoLong Estartu -- Gerhard Schmidt mailto:[EMAIL PROTECTED] Entwicklung adMaster network Tel.: +49 89 38356-334 Kaiserstrae 16 D-80801 Mnchen http://www.admasternetwork.net PGP signature
Re: Why Heap Tables doesn´t support auto increment colums
Im currently working on system for Managing http Session and would like to use a heap table for storing the session information. Session information is only of temporary intrest. But still I need an unique ID for reference with some other Tabels storing dtaa for the session. All these tables are Heap tables. So there is no Probelem if the ID generated by the auto_increment column is not unique when the Database server is restarted. There's a couple problems with that to begin with. First, you're storing state in a HEAP table. If the mysql server gets reset, all the sessions are lost. It would be tough to think you want to write your system so your database server cannot ever be restarted, especially when writing the data to a MyISAM table would probably be at a trivial loss of speed. Also, if you used an auto_incrementing column, you would be handing out sessionIDs sequentially. It would be trivial for somebody to usurp somebody else's sessionID by simply subtracting or adding 1 to their own. -Joe - Before posting, please check: http://www.mysql.com/manual.php (the manual) http://lists.mysql.com/ (the list archive) To request this thread, e-mail [EMAIL PROTECTED] To unsubscribe, e-mail [EMAIL PROTECTED] Trouble unsubscribing? Try: http://lists.mysql.com/php/unsubscribe.php
