Hey Yufeng,
2010/12/25 yufeng <[email protected]>:
> hi:
> "session.find<User>;" query all field of table,but sometimes I want to
> query only some field not all,How to implement it?I reference
To do this, you will need to define your own data structure to hold
the results. A Dbo object is always completely fetched. By far the
easiest way to have an ad-hoc data structure for these results is to
use a boost::tuple with as many elements as your SQL select clause
fetches arguments.
E.g. something like this:
typedef boost::tuple<long long, std::string, WDate, std::string,
std::string> BlogInfo;
dbo::collection<BlogInfo> aDBBlogs =
mpWebApp->mpDBSession->query<BlogInfo("SELECT
fuid,ftitle,fdate,freader,frun FROM tblog").where("fshow=1 AND
fshare=1").limit(miPageRows).orderBy("frun DESC,fuid
ASC").offset(offset_page);
Then use boost::tie() to get the individual fields of a single BlogInfo object.
Regards,
koen
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