Can I select a random row using NHibernate's ICriteria
API?
How do I select a Random Row using NHibernate's ICriteria API?
Asked Answered
Just as cundh2o said, it's DBMS-specific. But you can subclass the Order class and define your own custom ordering. For example, for SQL Server:
public class RandomOrder: Order {
public RandomOrder() : base("", true) {}
public override SqlString ToSqlString(ICriteria criteria, ICriteriaQuery criteriaQuery) {
return new SqlString("newid()");
}
}
2.1.2 compatible: public override SqlString ToSqlString(ICriteria criteria, ICriteriaQuery criteriaQuery) { return new SqlString("newid()"); } –
Tana
Use of Newid like this leads to terrible performance on medium-size to large tables though. –
Bernete
If you are not limited to using ICriteria, I might recommend using HQL instead for selecting a random row, since it may provide more flexibility to use the Random function supplied by your db provider.
IQuery q = NHibernateSession.CreateQuery("your hql statement here")
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