In the last episode (Sep 17), Christian Parpart said: > On Saturday 17 September 2005 08:34, Gleb Paharenko wrote: > > mysql> show create table ui\G; > > > > Table: ui > > Create Table: CREATE TABLE `ui` ( > > `uuid()` varchar(36) NOT NULL default '' > > I've been testing your example as I feel really much safer with UUIDs > instead of auto_increments, however, my column datatype is > VARCHAR(12) so 24bytes shorter than a usual UUID, although, all > uuid() SELECTs differ only in first 12 bytes - why?
The node-based uuid format that mysql generates has this format: time_low "-" time_mid "-" time_high_and_version "-" clock_seq_and_reserved clock_seq_low "-" node Node should be contant as long as you don't switch network cards in the machine, clock_seq is usually only reset across reboots (or mysql restarts since mysql currently generates its own uuid even if the OS provides a uuid generator), and time is a timestamp accurate to 100 nanoseconds. So assuming a single mysql server that doesn't get rebooted, you'll only ever see different values in the first three hyphenated fields. See RFC 4122 for more details. http://www.ossp.org/pkg/lib/uuid/ is a nice uuid library that includes a uuid decoder. -- Dan Nelson [EMAIL PROTECTED] -- MySQL General Mailing List For list archives: http://lists.mysql.com/mysql To unsubscribe: http://lists.mysql.com/[EMAIL PROTECTED]
