i have a table called orders and i have a column called Last Update (and an order object with a LastUpdate property). I want to construct a query using nhibernate to get the last 50 rows so i don't go to the database and get everything and then have to filter results in my application.
is this possible in nhibernate. I am trying to use the LINQ api
如果您使用的是Criteria,则使用SetMaxResults(50)并对日期时间进行降序排序。
Here's the LINQ version of this query.
var orders = session.Query<Order>()
.OrderByDescending(x => x.LastUpdate)
.Take(50);
Here's the screen shot of the code sample...
Here's the screen shot from NHibernate Profiler...
你可以使用SetMaxResults(50)
,虽然取决于你想要的50行(最新?第一?最后?),你可能也需要做一个SortBy表达式。
var orders = session.Query<Linq>()
.OrderByDescending(x => x.LastUpdate)
.Take(50);
In general case suggesing LastUdate
can be nullable using Linq2SQL you may write extension method to your IQueriable:
public static partial class FooTable
{
public static IQueryable<FooTable> LastUpdated(this IQueryable<FooTable> queryable, int count)
{
return queryable.Where(x => (x.LastUdate != null))
.OrderByDescending(x => x.LastUdate)
.Take(count);
}
}
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