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Hi all, I'm actually designing an internet application, and I'd like to know how to paginate the information retrieved from the database.
The problem is that I access a huge database (SQLServer 2000) and I don't want tho get all the records everytime I execute a query, I'd like to paginate the records and get them in different queries. I've thought of two methods to do that and I'd like to know which one is better, so if anybody knows it (or knows another way to solve it) please help me!
1.
Use SQL queries of the type
SELECT TOP x
FROM aTable
WHERE aTable.Id > @LastIdReceived
The problem I find in this method, is that I'm accessing a huge table (about 900.000 records) and is a complicated query (with Joins to a lot of other tables) so I think that if I do it this way, each time I have to execute the full query (and there's also the fact that with this way I can't know before the total amount of records affected by the query, I could do a COUNT first, but this would be another query)
2.
Create a temporary table of indexes with the query I need and then, retrieve the information I need by joining it with the real table (with the amount of records I need). The problem I see this way is that if there are a lot of users asking for queries at the same time, creating so many temporary tables might be inefficient.
So, If somebody has ever faced this problem I'd like to know which way is better or if there's another way I've not thought about.
Thanks.
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I've read it and I think it's more less what I'd thought as my second option. The problem I see is maybe creating the temporary table won't be efficient when a lot of users are asking queries since a lot of temporary tables will be created on the server (and I expect that situation), am I wrong and it won't affect too much ? Maybe there isn't a better way to do it.
thanks for everything.
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The site that Chris suggested would provide an efficient program because the temporary tables are created in memory, and then destroyed as soon as the stored procedure ends.
--
Andrew (first post in this forum  ).
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how about using the standard "allow paging" properties in VS.NET
it makes the paging very simple...
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First off, using a SQL statement such as "Select count(*) from here inner join this on here.id = this.id" will return a lot faster than actually having to return the actual results of the query. I would say that it is always a good idea to look at the size of your returning recordset when dealing with such large datasets.
Second, there are a few pages from another site that I have used in the past for searches that will result in large recordset. I would recommend this first page because you are using SQL Server 2000 you can write your query as a stored procedure and page through it. The second link allows you to do the same thing with a generic recordset via a SQL statement built on the client-side. Good Luck, hope this helps.
Links:
1. Paging Through Records Using A Stored Procedure
2. Paging Though Database Results N Records At A Time
Nick Parker
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Hi all, I'm actually designing an internet application, and I'd like to know how to paginate the information retrieved from the database.
The problem is that I access a huge database (SQLServer 2000) and I don't want tho get all the records everytime I execute a query, I'd like to paginate the records and get them in different queries. I've thought of two methods to do that and I'd like to know which one is better, so if anybody knows it (or knows another way to solve it) please help me!
1.
Use SQL queries of the type
SELECT TOP x
FROM aTable
WHERE aTable.Id > @LastIdReceived
The problem I find in this method, is that I'm accessing a huge table (about 900.000 records) and is a complicated query (with Joins to a lot of other tables) so I think that if I do it this way, each time I have to execute the full query (and there's also the fact that with this way I can't know before the total amount of records affected by the query, I could do a COUNT first, but this would be another query)
2.
Create a temporary table of indexes with the query I need and then, retrieve the information I need by joining it with the real table (with the amount of records I need). The problem I see this way is that if there are a lot of users asking for queries at the same time, creating so many temporary tables might be inefficient.
So, If somebody has ever faced this problem I'd like to know which way is better or if there's another way I've not thought about.
Thanks.
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Is there an equivalent to the C/C++ bitwise operators (&, |, ^) for use in SQL programming? And if not any suggestions on how to "best" emulate them. Using something like
select ...
from table t
where t.columnA in ( 1,2,3,5,7,9,11,13,15 );
or
select ...
from table t
where t.columnA in ( 4,5,6,7,12,13,14,15 );
doesn't sound too inviting from a maintenance standpoint. If I ever add another combination, I have to change all of the 'in' lists.
Thanks.
Chris Meech
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The Case construct I am referring to is like this:
Case {expression}
{result 1} : {code block}
{result 2} : {code block}
{result 3} : {code block}
{result 4} : {code block}
Else {code block}
End Case
I would like to do something like this in tSQL on SQL Server 2000. Rather than using daisy chained If statements.
Any ideas?
Jason Jystad
Cito Technologies
www.citotech.net
Sonork ID 11.9918
>-------------------------------------------------<
Every program has at least one bug and can be shortened by at least one instruction -- from which, by induction, one can deduce that every program can be reduced to one instruction that doesn't work.
>-------------------------------------------------<
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Thanks!
You are correct, I do not have access to the BOL from where I am. Thanks for the site, I was looking for something like that online, but I wasn't having much luck.
Jason Jystad
Cito Technologies
www.citotech.net
Sonork ID 100.9918
>-------------------------------------------------<
Every program has at least one bug and can be shortened by at least one instruction -- from which, by induction, one can deduce that every program can be reduced to one instruction that doesn't work.
>-------------------------------------------------<
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YES...
Like this
Select
CASE FieldNumber
WHEN 0 THEN "Cero"
WHEN 1 THEN "One"
.
.
.
WHEN 9 THEN "nine"
ELSE "No Value"
END
From
MyTable
Best Regards
Carlos Antollini.
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Yes, you are correct, it is a lot eaiser to write a Case statement than a nested if statement, especially inside those small stored procedure window of SQL Server 2000.
(CASE WHEN Cust_Name = 1 THEN 'Good Customer' ELSE 'BAD Customer' END)
or you can do nested Case statements such as:
(CASE WHEN Cust_Name = 1 then 'Good Customer' ELSE(CASE WHEN Cust_Name = 2 THEN 'SO-SO Customer' ELSE 'Bad Customer' END) END)
Hope this helps.
Nick Parker
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In my application I first connect to SQL server using MFC ODBC classes,
then the same thread tries to to create ADO Connection object
and it fails. What's strange is that if my application first connects to MSAccess using MFC ODBC classes then it can create ADO just fine.
What's the deal with SQL ODBC drivers and ADO? 
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Make sure you have loaded the Ole Libraries
I think in MFC you need to call AfxOLEInit or something like that.
ADO will only work if you load this
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Hi,
I'm trying to change the value of a recordset's property. The property is "scroll backwards" (want to change from false to true).
I opened a recordset, and then I got it's properties. I got the wanted property(according to it's index), but I can't change the value - I get an error saying that "the operation can't be done when the object is open".
Which object is the error talking about?
Do I need to change the property after openning the recordset?
What am I doing wrong?
Can someone please send me a code example of what should I do...???
Thanks.
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Take a look at your CursorType if is forward only it might be the source of your problem.
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HI.
I´m developing a database application using ado and, although it´s a large program i don´t want to use more than 2 or 3 open connections.
The problem is that i can´t define a global connection pointer, right now, i can only make it work creating a new con in every cpp file.
I´ve tryed defining a global pointer in every way i know but I´m allways getting memory or even weirder errors.
Can anyone help me out?
Pedro Besteiro
LSI systems integration
Pedro Besteiro
LSI systems integration
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Just define pointer at connection in any your class (as class member) and set it everytime when constructing class.
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I am trying to design a table which encompasses a Parent-Child relationship.
I essentially have three classes of data that can be stored in this table. The Level 1 items are the parents of Level 2s and Level2s are parents of Level 3s.
I was wondering what is the more recommended approach to dealing with these situations? What constraint enforcement mechanism is deemed better? Would it be better to use triggers or should i used some form of a foreign key on the same table?
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I am using SQL 7.0 with MDAC 5.0. One of the stored procedure has a Select statement followed by Insert statement.
If the Insert statement fails due to any reason I cannot get the error in ADO Error collection object. But strangely if I put the insert first and then the select, the ADO error collection is filled ?
What is wrong or What am I doing wrong ?
Thanks
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Just as the title!!!!!!
Thanks in advance!
Please pardon my weak English!
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You can try using something like this:
<br />
#pragma warning(push)<br />
#pragma warning(disable: 4146)<br />
#import "\program files\common files\system\ado\msado25.tlb" rename("EOF", "adoEOF")<br />
#pragma warning(pop)<br />
then you can call ADO directly using smart pointers (e.g., ADODB::_RecordsetPtr). It's not MFC dependant.
See more info in MSDN on how to do this.
Furor fit laesa saepius patientia
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Have an application that is targetted for both SQL Server 7 and 2000 and MSDE.
Is there a known problem with the Transaction log within MSDE that prevents it from shrinking ? I'm calling various things like DBCC SHRINKFILE through Query Analyser but it often doesn't have any effect.
Net result is that my transaction log keeps growing and growing - not something to ship to customers.
Does anyone know of a dirty way around this problem ?
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