Tuesday, June 23, 2009

Generic guide for Pagination in Web Pages

Pagination Steps.
The only variable needed to be defined: pageSize, say 2

1. Select total no of rows (noOfRows, say 5) from the database table into a variable.
2. Calculate ceil of noOfRows/pageSize, 5/2 = 2.5, ceil(2.5) 3.
3. So we will have 3 pages.
4. Now create links on the page showing 3 links ( 1,2,3 ).
5. User clicking any of them should send the value to the server.
6. Say user selects 2 (pageNum), now we need to fetch 2 and 3rd record.
7. Dividing the data into rows with pageSize 2, ({1,2},{3,4},{5}).
8. We need to calculate first and last record to be fetched from the database.
9. Calculate the value as
last = (pageSize * pageNum), 4
first = last-pageSize+1, 4-2+1, 3
10. Fire the query now(oracle):
select * from user where rownum between first and last.

Done :)