Re: Cursor Example Needed

On Oct 28, 2013, at 6:50 PM, Adrian Klaver <adrian(dot)klaver(at)gmail(dot)com> wrote:

> On 10/28/2013 04:36 PM, Perry Smith wrote:
>>
>> On Oct 28, 2013, at 6:13 PM, John R Pierce <pierce(at)hogranch(dot)com> wrote:
>>
>>> On 10/28/2013 3:58 PM, Adrian Klaver wrote:
>>>> The docs do a good job of illustrating:
>>>>
>>>> http://www.postgresql.org/docs/9.3/interactive/plpgsql-cursors.html
>>>
>>> thats for cursors created within a plpgsql function.
>>>
>>> I think what the OP wants is a top level cursor, which is a different thing...
>>>
>>> see
>>> http://www.postgresql.org/docs/current/static/sql-declare.html
>>> http://www.postgresql.org/docs/current/static/sql-fetch.html
>>> http://www.postgresql.org/docs/current/static/sql-close.html
>>>
>>> the fetch page shows an example of the complete usage in the context of a database transaction.
>>
>> Thank you to Merlin. I now understand better where my confusion was.
>>
>> John:
>>
>> Those examples are great except there is no way that I know of to loop on
>> the "top level" as you call it. I'm trying to do something that I can give to
>> psql which will loop through the entire set that is produced.
>
> The FETCH example shows you how. You do not have FOR but you do have FORWARD and if you DECLARE SCROLL, BACKWARD. If you need to do actions on each row as it is fetched then you will probably need to do it in a function. Your original post though was concerned with dealing with an out of memory error caused by returning to large a result set at one time and that can be handled in psql as illustrated.

Yes. I finally understand your (or someone's) original reply.

Thank you to all who helped me out.

Perry