Q)
why do we use queries?
Ans:queries are user interactive, faster,
compiles, reusable components
query,
queryrun,querybuilddatasource,querybuildrange
if(qr.prompt())
Q)
what is difference between temporary table and container???
Ans:when there  are more than 50 columns then  we go for  temp tables
and also there are some advantages using
temp tables - we can create index, methods , fieldgroups
Q)
How  do u share tables across the
companies????
Ans: Tablecollections and virtual companies
Q)
when is configuration key used??
Ans:To  enable 
and disable the features for all  users
[tables, fields, indexes, form controls, edt.enum...etc]
Security  key   for   set  of  users  or  usergroups
- tables, forms, report, menuitems etc
RLS [Record level security]
Q)
What are display methods?
Ans:Display 
methods  will help you to show the
data from some other table or hard-coded strings..these are not bound controls
and we cannot use filter or sorting options