问题
How do you pass a list of things for the 'in' clause in Nhibernate HQL?
e.g.
// data input from the user interface, not known at compile time
object[] productIds = {1, 17, 36, ... };
string hqlQuery = @"
from Product as prod
where prod.Id in ( ? )";
HqlBasedQuery query = new HqlBasedQuery(typeof(Product), hqlQuery, productIds)
ActiveRecordMediator.ExecuteQuery(query);
Now, this isn't going to work, as much as I wish it would! Am I really stuck doing something like this:
// data input from the user interface, not known at compile time
object[] productIds = {1, 17, 36, ... };
string hqlQuery = @"
from Product as prod
where prod.Id in ( {0} )";
// build string array of the right number of '?' characters
string[] paramStringArray = new String('?', productIds.Length).ToCharArray().Select(item => item.ToString()).ToArray();
// join to make '?, ?, ?, ?, ?'
string parameterString = string.Join(", ", paramStringArray);
hqlQuery = string.Format(hqlQuery , parameterString);
HqlBasedQuery query = new HqlBasedQuery(typeof(Product), hqlQuery, productIds)
ActiveRecordMediator.ExecuteQuery(query);
That's just ugly and I've tried to make it as not ugly and short as I can. If anyone has a nice way of accomplishing this please let me know.
Also I see Jeff asked a similar questions about how to do this on SQL: Parameterize an SQL IN clause This is basically the same question I just want to know how to do it from HQL. That's why I'm making the titles so similar.
回答1:
Use SetParameterList()
.
Code snippet from billsternberger.net:
ArrayList stateslist = new ArrayList();
stateslist.Add("TX");
stateslist.Add("VA");
string hql = String.Format("FROM Contact c where State in (:states)");
SimpleQuery<Contact> q = new SimpleQuery<Contact>(hql);
q.SetParameterList("states", stateslist);
Contact[] result = q.Execute();
来源:https://stackoverflow.com/questions/2388021/parameterizing-a-hql-in-clause-using-hqlbasedquery