What is advantage of QVD?

[#1]

Thanks Mark,

Now i understood a bit. I read the advantage of using QVD fie in the reference manual. consider the scenario below. Suppose i have a table contains 5 lacs records. To create a QVD i have to write a Query to fetch records from the table then i have to write STORE command to create a QVD from the extracted records and then create a QVW document using that QVD file. If i'm not using QVD instead fetching data directly from data source to create a QVW document.

I want to know if there is any difference in time consuming by fetching the records.

Main advantage is, fetching records from QVD is faster than fetching records from Data base. and also same QVD can be used in multiple applications.

Regards,
-Raghu

[Anonymous]

I'd like to point out to at least one additional advantage.
When you load a large amount of data from the database, it's a significant workload on the database server. Other users of the system will be unhappy (know this from the real life experience).
But if you load the same amount of data once, probably in the middle of the night, store it in QVD, and after that during the daytime load it from QVD and only new data from the database - no much load on database server, and everybody is happy.