Re: Question about serial vs. int datatypes
От | Paul Thomas |
---|---|
Тема | Re: Question about serial vs. int datatypes |
Дата | |
Msg-id | 20030608091125.A8133@bacon обсуждение исходный текст |
Ответ на | Question about serial vs. int datatypes (Lynna Landstreet <lynna@gallery44.org>) |
Список | pgsql-general |
On 05/06/2003 21:05 Lynna Landstreet wrote: > Anyway: I'm converting a FileMaker Pro database into PostgreSQL, and have > a > question (actually, tons of questions, but I'll stick to one for now). > Each > of the three major database files in FMP (equivalent to tables in > PostgreSQL) has a number field as a primary key which is incremented > serially as new records are added. Nice and simple, and the same thing a > lot > of PostgreSQL databases use. > > But... when converting an existing database that already has several > hundred > records in it, I can't make that field serial in PostgreSQL, can I? > Because > I don't want the existing records renumbered - that would break the links > between the different tables. But if I make the id number just a smallint > field, then I'm stuck incrementing it manually after the conversion. Is > there any way around this? Any way to import the existing records with > their > id number intact, and then have it switch to serial after that for new > records? > > Any advice would be appreciated... Looking at the docs and after a bit of playing around with 7.3.3, I think this may work: 1) I believe PG _will_ accept the serial numbers you insert so importing the data with your serial number fields should work. 2) For each serial type you will find that PG has a created a Sequence object with a name of the form tablename_columnname_seq. After the import, you will need to set this to the max value of your serial column with SELECT pg_catalog.setval("sequencename", value, true); HTH -- Paul Thomas +------------------------------+---------------------------------------------+ | Thomas Micro Systems Limited | Software Solutions for the Smaller Business | | Computer Consultants | http://www.thomas-micro-systems-ltd.co.uk | +------------------------------+---------------------------------------------+
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