actually source of the crystal report is Businessview. so u
must create universe. then after based on the Businessview u
generate the reports. otherwise to generate reports is not
possible by using crystal report suite. u want ro generate
the reports without the unverse to take personal
datafiles.crystal report separate installation is there.
TXT,PDF,.. type of reports work in Crystal reports separate
installation.

iam sorry i really did not understand what u mean to say?
my question is main difference to choose business objects
reporting tool?bez crystel also an reporting tool using
which i can create various reports directly from database
.so what is the main advantage of using b.o.?

Main difference is ROLAP (Relational OLAP) supported by BO 
and not by Crystal Reports. ROLAP meaning is you can try to 
generate the universe using SQL's from several data sources
(whatever you call like SQL Server,ORACLE etc;).In Crystal 
Reports if you try to add more that one datasource that's 
it!! the verify database option will be disabled(which 
means it does not support)

The biggest difference is that Crystal reports are used 
for "canned" reporting while BO is used for adhoc 
reporting.

Here you go.

The main purpose of the universe is, it acts as an 
interface between database and BO. So a non technical guy 
can also create a report using the universe by drag/drop 
the objects. 
Once the universe had built, you no need to again create 
queries in Crystal reports also, you can simply use the 
universe as source, it will save time. 
If the universe is not satisfying your report requirements 
then you need to go for other sources.

Hope your doubt is clear.