Re: [SQL] Stepping through a table.
От | Matthew Hagerty |
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Тема | Re: [SQL] Stepping through a table. |
Дата | |
Msg-id | 4.1.19990816164740.00c9fda0@mail.venux.net обсуждение исходный текст |
Ответ на | Re: [SQL] Stepping through a table. (Herouth Maoz <herouth@oumail.openu.ac.il>) |
Ответы |
Re: [SQL] Stepping through a table.
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Список | pgsql-sql |
Thanks, I was thinking that's what cursors did, but I can't find a good source anywhere that actually tells you that you are reading one record at a time instead of submitting a whole query where the results are place in memory. You mentioned that cursors are read only. Can I do update statements while navigating with cursors? Or do they lock the records they are reading? Again, thank you. Matthew At 12:19 PM 8/16/99 +0300, Herouth Maoz wrote: >At 05:58 +0300 on 16/08/1999, Matthew Hagerty wrote: > > >> If I need to process each record in a table, how can I step through each >> record? I suppose I could write a query to return all records and fetch >> each row that way, but that would be a big memory pig, no? Also, the table >> could get pretty big. Is there some way to navigate a table, maybe >> fetching one record from the disk at a time, or something similar? > >I guess you are looking for cursors. Read about it on page 154 of the >PostgreSQL user guide, or check out the manpage about "declare". Note that >PostgreSQL cursors are readonly, and can't be used to update information. > >Herouth > >-- >Herouth Maoz, Internet developer. >Open University of Israel - Telem project >http://telem.openu.ac.il/~herutma > >
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