Fetching a partial range of selected result rows from the client side

Question

It has been a while since I started trying to solve this Oracle puzzle.
Basically, what I need it is a way to fetch from the client side a run-time
defined range of result rows of a arbitrary SELECT query.
In low-end databases like MySQL I can do it simply by appending the LIMIT
argument to the end of the SELECT query statment passing the number of
the first row that I want to be returned from the server from the total
result rows available in the result set and the maximum number of rows
that it may return if available.
In higher end databases I am supposed to use server side cursors to skip
any initial rows before the first that I want to retrieve and fetch only
the rows I want up to the given limit.
I am able to achieve this with PostgreSQL and Microsoft SQL server, but I
am having a hard time with Oracle. The main problem is how do I fetch
result rows from a server side cursor and have their data returned to a
client side in a result set like in a straight SELECT query?
I was able to create a cursor and fecth a row into a server side record
variable with the following PL/SQL code.
DECLARE
CURSOR c IS SELECT * FROM my_table;
my_row c%ROWTYPE;
BEGIN
OPEN c;
FETCH c INTO my_row;
CLOSE c;
END;
I want to do this from PHP, so I don't have client side ESQL variables to
store the result set data structure. Anyway, if I can do it just with
SQLPlus I should be able to do it in PHP.
If I do straight SELECT I can get the result set, but in a PL/SQL script
like the one above I don't seem to be able to select the data in the
fetched row record to have returned to the client. Does a straight SELECT
query sends the result rows to a default client side variable?
If anybody can help, I would appreciate if you could mail me at
[email protected] because I am not able to access this forum all the time in
the Web. BTW, is it possible to access this forum by e-mail?
Thanks in advance,
Manuel Lemos
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Answer 1

Hello Jason,
On 03-Feb-00 05:34:14, you wrote:
I'm not sure I totally understand your problem, but I think you might be able
to solve it by using the ROWNUM variable. ROWNUM returns the sequenc number
in which a row was returned when first selected from a table. The first row
has ROWNUM = 1, the second has ROWNUM = 2, etc. Just remember that the
ROWNUM is assigned as soon as it's selected, even before an order by. So if
you have an order by clause, it'll mess it up. Here's an example. I hope
that helps.I though of that before but it doesn't help because if you use ORDER BY the
first result row might not have ROWNUM=1 and so on. Another issue is that
I want to be able to skip a given number of result rows before returning
anything to the client.
The only way I see to do it is to get the rows with server side cursor.
But how do I return them to the client? Where does a normal select returns
the rows? Isn't there a way to specify that the fetch or something else
return the rows there?
Regards,
Manuel Lemos
Web Programming Components using PHP Classes.
Look at: http://phpclasses.UpperDesign.com/?user=[email protected]
E-mail: [email protected]
URL: http://www.mlemos.e-na.net/
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