crystal report & sub report

am developing a payroll project in vb.net with SQL server, in 开发者_运维问答this am using SEAGATE crystal report for taking reports, if i use more than 10 sub reports in single report weather it affect my project efficiency or it will take more time

Yes, it will take more time since you're in effect probably running 10 different queries and the reporting tool is probably having to link the results of all of those queries.

I've written reports with 3 or 4 subreports, but usually more is unnecessary. I would try to think of a workaround for that many subreports - usually there's a way. (For example, use a column as a toggle for showing/hiding or grouping data.)

Actually it is hard to say, how your subreports affect performance. I've designed reports, where using subreports makes entire report run faster - sometimes it is not so easy to build underlying query to be more efficient than many simpler queries for subreports.

One example is A-B-A-C type reports, where there are many one-to-many relations from master table/query (A) to subtables/queries (B,C) AND users want to see all BC type data at once (not on-demand). For single query it would be A*B*C rows to process (and implement nasty logic to show-hide sections), using subreports you can deal with A*(B+C) total rows to process and display.

But when you use subreport to display only some total value, then often it is more efficient to aggregate it already in master view - takes less time both in server and while transmitting data. Crystal Reports formatting time is usually negligible compared to query execution time.

Like always, optimum strategy depends on particular report needs.