As far as I know, the QueryOver api does not allow you reference an alias by name, but rather you use a typed object. How can I add a restriction to my query that targets the alias?
For example, I would like to accomplish something similar to the following:
var query = session.QueryOver<Person>().JoinQueryOver(x => x.Dogs, () => dogAlias);
return query.Where(Restrictions.Disjunction()
.Add(Restrictions.Like("Name", searchQuery, MatchMode.Anywhere))
.Add(Restrictions.Like("dogAlias.Name", searchQuery, MatchMode.Anywhere)));
instead of:
Restrictions.Like("dogAlias.Name", searchQuery, MatchMode.Anywhere)
use:
Restrictions.On(() => dogAlias.Name).IsLike(searchQuery, MatchMode.Anywhere)
So, the complete query would become:
var query = session.QueryOver<Person>()
.JoinQueryOver(x => x.Dogs, () => dogAlias);
return query.Where(Restrictions.Disjunction()
.Add(Restrictions.On<Person>(p => p.Name).IsLike(searchQuery, MatchMode.Anywhere))
.Add(Restrictions.On(() => dogAlias.Name).IsLike(searchQuery, MatchMode.Anywhere)));
Related
Finally tracked down my error which is a result of the query. I have an nhibernate query using a Restrictions.In. Problem is once query executes if no results returned query throws error immediately. Is there another restriction that I can use. I know if I was writing a linq query I could use the .Any to return bool value and go from there is there something similar I can do in this instance?
carMake is passed in
myQuery.JoinQueryOver(x => x.Car)
.Where(Restrictions.In("VIN",
Trades.Where(x => x.Car.Make.ToLower() == carMake.ToLower())
.Select(x => x.Car.PrimaryVIN)
.ToList()));
Assuming that Trades is a list of objects you can use .WhereRestrictionOn() instead. Try this (I split the code for better readability):
var vinsWithCarMake = Trades
.Where(x => x.Car.Make.ToLower() == carMake.ToLower())
.Select(x => x.Car.PrimaryVIN)
.ToList<string>();
var carAlias = null;
var result = myQuery.JoinAlias(x => x.Car, () => carAlias)
.WhereRestrictionOn(() => carAlias.VIN).IsInG<string>(vinsWithCarMake)
.List();
How do I add optional where clauses with QueryOver?
TL;DR
I am trying to implement a search form for an application and use QueryOver.
Some of the search parameters are optional.
var query =
myDatabase.QueryOver(() => customerAlias)
.JoinAlias(() => customerAlias.Projects, () => projectAlias)
.Where(() => projectAlias.IsClosed >= 1)
... possibly add more stuff
QueryOver is deferred in execution as for usual Linq statements. It will only execute when you force it to by calling a finalising method such as .List<T>().
var query =
myDatabase.QueryOver(() => customerAlias)
.JoinAlias(() => customerAlias.Projects, () => projectAlias)
.Where(() => projectAlias.IsClosed >= 1);
if (myCondition) {
query = query.Where(...);
}
var result = query.List<T>(); //Or however else you want to make it execute.
You should still be able to access the in-line aliases too this way.
how can I do this with queryover and a subquery?
FakturaObjektGutschrift fog = null;
int[] idS = Session.QueryOver(() => fog)
.SelectList( list => list
.SelectMax(() => fog.Id)
.SelectGroup(() => fog.SammelKontierung)
).List<object[]>().Select(x => (int)x[0]).ToArray();
And using the ids in another query
IQueryOver<Beleg, Beleg> sdfsd = Session.QueryOver(() => bGut)
.AndRestrictionOn(() => fog.Id).IsIn(idS); //iDs is a list of int.
I would like do this with a subquery because there is a limitation on the number of parameters for a SQL query. How do I do this?
How do I write the first query, but without selecting the SelectGroup()? This is exactly where I got stuck.
Group by without projection in QueryOver API is currently not supported link.
You can use LINQ to create the projection in a subquery:
var subquery = Session.Query<FakturaObjektGutschrift>()
.GroupBy(x => x.SammelKontierung)
.Select(x => x.Max(y => y.Id));
var query = Session.Query<Beleg>()
.Where(x => subquery.Contains(x.Id));
If you really needs QueryOver to create more complex queries check this solution link.
There is an entity Effort that has a property List and a property AdType
We have several adTypes enum objects and specialLists enum objects to select IList<Effort>
I do it in this way:
return NHibernateSession.QueryOver<Effort>()
.JoinQueryOver(effort => effort.AdType)
.WhereRestrictionOn(adType => adType.Id)
.IsIn(adTypes.Select(adt => (long)adt).ToList())
.Clone()
.JoinQueryOver(effort => effort.List)
.WhereRestrictionOn(list => list.Id)
.IsIn(specialLists.Select(sl => (long)sl).ToList())
.List<Effort>();
as u can see I use a strange Clone() method that doesn't have any description. It works great.
In what way do you use QueryOver for such queries?
.JoinQueryOver(effort => effort.AdType) will return a QueryOver with a subtype, here AdType IQueryOver<Effort, Adtype> instead of the original IQueryOver<Effort, Effort>. The first generic argument is the queryType and the second the type on which the methods are operating on. If you clone in between the whole query is copyied and returned as the basequery IQueryOver<Effort, Effort>.
To prevent the QueryOver to switch to the subtype there is JoinAlias which creates an alias instead of descending.
AdType adAlias = null;
ListType listAlias = null;
return NHibernateSession.QueryOver<Effort>()
.JoinAlias(effort => effort.AdType, () => adAlias)
.JoinAlias(effort => effort.List, () => listAlias)
.WhereRestrictionOn(() => adAlias.Id).IsIn(adTypes.Cast<long>().ToList())
.WhereRestrictionOn(() => listAlias.Id).IsIn(specialLists.Cast<long>().ToList())
.List<Effort>();
not that if you only Restrict on the Id of adtype and listtype then
return NHibernateSession.QueryOver<Effort>()
.WhereRestrictionOn(effort => effort.Adtype.Id).IsIn(adTypes.Cast<long>().ToList())
.WhereRestrictionOn(effort => effort.List.Id).IsIn(specialLists.Cast<long>().ToList())
.List<Effort>();
I'm using NHibernate 3.0 with both the LINQ provider and QueryOver. Sometimes I want to eager load related data, and there comes the method "Fetch" to the rescue, both in LINQ and QueryOver. Now I have a special scenario where I want to eager load a property not directly on the second level, like:
Foo f = ...;
f.A.B.C
with LINQ there's no problem, as you can "chain" fetches with the method "ThenFetch", like:
var result = Session.Query<Foo>().Fetch(a => a.A).ThenFetch(b => b.B).ThenFetch(c => c.C).ToList();
In QueryOver there's no such method, so how can I achieve the same result?
Thanks in advance.
I actually managed to solve this problem using two different approaches:
Approach one:
Session.QueryOver<Foo>().Fetch(x => x.A).Fetch(x => x.A.B).Fetch(x => x.A.B.C)
Approach two:
A a = null;
B b = null;
C c = null;
Session.QueryOver<Foo>()
.JoinAlias(x => x.A, () => a)
.JoinAlias(() => a.B, () => b)
.JoinAlias(() => b.C, () => c)
Both work (altough I'm not exactly sure if one of them generated "inner" and the other one "outer" joins).
Just as a curiosity, I'll post the reply they gave me on the NHibernate Jira:
query
.Fetch(p => p.B)
.Fetch(p => p.B.C) // if B is not a collection ... or
.Fetch(p => p.B[0].C) // if B is a collection ... or
.Fetch(p => p.B.First().C) // if B is an IEnumerable (using .First() extension method)
I think you can do that with JoinQueryOver
IQueryOver<Relation> actual =
CreateTestQueryOver<Relation>()
.Inner.JoinQueryOver(r => r.Related1)
.Left.JoinQueryOver(r => r.Related2)
.Right.JoinQueryOver(r => r.Related3)
.Full.JoinQueryOver(r => r.Related4)
.JoinQueryOver(r => r.Collection1, () => collection1Alias)
.Left.JoinQueryOver(r => r.Collection2, () => collection2Alias)
.Right.JoinQueryOver(r => r.Collection3)
.Full.JoinQueryOver(r => r.People, () => personAlias);