How to retrieve partial data in SQL Server ?

[samit majumdar]

I am trying to display 4 columns of a particular table. The browser

is displaying 50 records per page. 'Next' and 'Previous' buttons are

there for navigating through all the records. It may have even 1

million or more records. The table may have n number of records. I am

not getting any problem if the record size is approximately 50,000.

But for large number of records say, 1 lac or more, the browser is

taking too much time...roughly, for 1 lac record it is taking 35

seconds and for 2.5 lac record it is taking 4 minutes...as the no of

records fetched increases...page loading time also increases

exponentially. So, my aim is to collect partial data from the table

and display it. In oracle I can manage it using rownum and minus

clause, efficiently. But in SQL Server I am not able to handle it,

using those technique. My application runs both on Oracle and SQL

Server. Can anybody help me?

For more clarity :::: I want to collect 1 to 50 records from the

table. next time I want to collect records from 51th. position to

100th. position. And then from 101th. position to 15oth. and so on.
Of course in SQL Server.

I am writing my code in JSP.

Thanks -

Samit
[ July 21, 2005: Message edited by: samit majumdar ]

[Stan James]

Here are some notes on prior pagination discussions. See if any of these ideas fit your situation. Let us know if you think of better ones!

I. Repeat the query for each new request.
   Algorithm
      Client requests page 1
      Execute the query
      Return rows for page 1
      Client requests page 2
      Execute the query
      Skip rows for page 1
      Return rows for page 2
   Variation
      Most RDBMS vendors support returning a specified range of row numbers.
      Efficiency varies. May not help much when combined with "order by"
   Pro/Con
      Pro: Stateless. Nothing is cached between requests.
      Pro: Simple. Every request is the same.
      Pro: Up to date with any inserts or deletes in the database.
      Con: Database and time intensive. Might be repeating large,
           expensive queries - if users really do ever page fwd.
      Con: Not guaranteed consistent. If other processes are inserting and
           deleting rows, paging fwd or bkwd might skip rows. Fwd then Bkwd
           might not give the same rows.
   Notes   We have used this with mainframe requests where even the nastiest
           queries were fast and the server had no options for storing state.
           We have used row number schemes for client requests, and the highest
           key on a page for page forward only action.
II. Hold the query results on the server
   Algorithm
      Client requests page 1
      Execute query
      Cache complete result set or just PKeys
      Return rows for page 1
      Client requests page 2
      Get rows from cache or get PKeys from cache, rows from database
      Return rows for page 2
   Pros/Cons
      Pro: Does NOT repeat the query
      Pro: Self consistent - fwd then bkwd will give identical results
      Pro: Can share cached results if two users have identical requests
      Con: Big cache in memory or someplace close to it
      Con: Complexity for cache, time-out
III. Hold a scrolling cursor on the server
   Algorithm
      Client requests page 1
      Execute query with a cursor
      Fetch & return rows for page 1
      Client requests page 2
      Fetch & return rows for page 2
   Pro/Con
      Pro: Does not repeat the query
      Pro: Very small state - just a connection & cursor
      Pro: Self consistent
      Con: More open connections. Might hold open one db connection
           per user
      Con: What does this do to the db? Doesn't it cache rows not yet
           fetched?
      Con: Complexity for time-out

[Ganesh Gowtham]

if i want to develop the list which shows only 10 records at a time but the table may have 50,000 qualifiing
records for my query ..i have to naigaet using the prev and fwd buttons what is the best way to do....
i tried setFetcsize(num); but in vain...
is there any link that i can use it for iterate the resultset (10 records at a time) ,
i stored the romnum in session for each fwd button i increased by "10" and send to database is this
way appreciatable..
Pls suggest