Any Interest? The DBMS_JOB package is supplied by Oracle to allow the running of procedures at regular intervals. Unfortunately the INTERVAL parameter is limited to 128 characters, which prevents you from getting very complex (user defined functions [in the interval parameter] do not work well - according to Fuerstein in his book Oracle Built In Packages).
The situation is eased somewhat by the fact that the NEXT_DATE parameter can be supplied to the procedure as an in/out parameter - and the procedure can contain whatever code is necessary to calculate when next to run. This is all very well, but custom coding scheduling routines can quickly become tedious. On the basis of "do it once and get it over with" I have written a function called NEXT_DATE which I have wrapped in a package called CRON. There is a Unix program called cron which runs jobs on a regular basis. Although the scheduling data supplied to cron is simple and concise, complex schedules are easy to specify. The NEXT_DATE function takes in a cron schedule string and returns the next date that conforms to the schedule - or you can supply a cron schedule and a date and it will return the first date after the supplied date that conforms to the schedule. At the moment it is not very friendly on the error detection front. A VALUE_ERROR is returned if it deems the cron schedule to be invalid. You will also get a VALUE_ERROR if the next valid date is more than twenty seven years in the future. DBMS_OUTPUT is used to display error messages which will hopefully give you a clue. This will be improved if I receive enough complaints ( and suggestions for improvements). THE CRON SCHEDULE A cron schedule consists of five components, each separated from the next by a space. The syntax is identical for all components. The components represent Minute in Hour Hour in day Day in month Month in year Day of Week - A bit of a bugger this one. In Unix land the day numbering runs from 0-6 with 0 being Sunday. In Oracle the day numbering depends on the setting of NLS_TERRITORY. I have chosen to go with ISO standard 8601:1998 which runs from 1-7 with 1 being Monday. This is so close to the Unix convention that I can interpret Unix cron schedules correctly. Curiously, Oracle do not provide a date format which supplies this number. The ISO week number is available with the format 'IW', but not the ISO day number. If you have a field of type date called dt, you can obtain the ISO day number with ( trunc(dt) - trunc(dt ,'IW') ) + 1 A component can consist of an asterisk * which represents all valid values or a number of elements separated by a comma (if only one element is supplied, forget the comma). An element can be a single number - valid for the component (32 in "Day in month" is invalid) or two numbers separated by a hyphen - which represents a range. EXAMPLES Run every hour on the hour 0 * * * * Run twice every hour, on the hour and on the half hour 0,30 * * * * Run twice every hour, on the hour and on the half hour between 08:00 and 16:59 0,30 8-16 * * * Run twice every hour, on the hour and on the half hour between 08:00 and 16:59, Monday to Friday 0,30 8-16 * * 1-5 Run at 11:12 every Friday the 13th 11 12 13 * 5 Run at 04:00 every leap year on february 29 0 4 29 2 * Run at 04:00 every leap year on february 29 when february 29 is a Thursday 0 4 29 2 4 Garry Gillies Database Administrator Business Systems Weir Pumps Ltd 149 Newlands Road, Cathcart, Glasgow, G44 4EX T: +44 0141 308 3982 F: +44 0141 633 1147 E: [EMAIL PROTECTED] CONFIDENTIAL: The information contained in this email (including any attachments) is confidential, subject to copyright and for the use of the intended recipient only. If you are not the intended recipient please delete this message after notifying the sender. Unauthorised retention, alteration or distribution of this email is forbidden and may be actionable. Attachments are opened at your own risk and you are advised to scan incoming email for viruses before opening any attached files. We give no guarantee that any communication is virus-free and accept no responsibility for virus contamination or other system loss or damage of any kind. -- Please see the official ORACLE-L FAQ: http://www.orafaq.net -- Author: Garry Gillies 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).