Re: Workaround or user defined type
От | Josh Berkus |
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Тема | Re: Workaround or user defined type |
Дата | |
Msg-id | web-500060@davinci.ethosmedia.com обсуждение исходный текст |
Ответ на | Workaround or user defined type (Juan Jose Natera Abreu <jnatera@net-uno.net>) |
Список | pgsql-novice |
Juan, > I am working on a trouble ticket system in Perl, usually those > systems > identify a ticket by a string composed of DDMMYYYY-SERIAL, (DD = day, > MM= month, YYYY= year, SERIAL= a serial number for the date string). > > I am not sure how to generate these identifiers, in case I generate > them manually i must provide a mechanism to insure the sequence, like > locking the table for reading/writing, get the last value, insert the > new one and then release the lock. However i think this could be a > big > performance killer. Any ideas? Yes. It is STRONGLY reccommended that you deal with this by splitting the ID into two or more columns, so that each piece may remain atomic. Then your formula is simple: 1. Save the first column through a to_char(DATE) system; and 2. Have the second column default off an INTEGER DEFAULT NEXTVAL('ticket_seq') column; 3. Each day, at exactly 00:00:01 run a SETVAL('ticket_seq',1). See? *much* easier than mucking around with user-defined types. -Josh ______AGLIO DATABASE SOLUTIONS___________________________ Josh Berkus Complete information technology josh@agliodbs.com and data management solutions (415) 565-7293 for law firms, small businesses fax 621-2533 and non-profit organizations. San Francisco
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