I got this query
var pc = _session.Query<ValutaHistory>()
.Where(x => x.Valutum.ValutaBetegn == updateLine.ProductCurrency)
.Fetch(x => x.Valutum)
.OrderByDescending(x => x.ValutaHistoryID)
.First();
But it results to this SQL:
select TOP (1) valutahist0_.ValutaHistoryID as ValutaHi1_187_0_,
valutum1_.ValutaID as ValutaID191_1_,
valutahist0_.Kurs as Kurs187_0_,
valutahist0_.ts as ts187_0_,
valutahist0_.cts as cts187_0_,
valutahist0_.nts as nts187_0_,
valutahist0_.KjopKurs as KjopKurs187_0_,
valutahist0_.ValutaID as ValutaID187_0_,
valutum1_.ValutaBetegn as ValutaBe2_191_1_,
valutum1_.KursDato as KursDato191_1_,
valutum1_.Kurs as Kurs191_1_,
valutum1_.Enhet as Enhet191_1_,
valutum1_.Myntsort as Myntsort191_1_,
valutum1_.BrukesSalg as BrukesSalg191_1_,
valutum1_.Aktiv as Aktiv191_1_,
valutum1_.ts as ts191_1_,
valutum1_.cts as cts191_1_,
valutum1_.nts as nts191_1_,
valutum1_.TallKode as TallKode191_1_,
valutum1_.Symbol as Symbol191_1_,
valutum1_.TallKode1 as TallKode14_191_1_,
valutum1_.TallKode2 as TallKode15_191_1_,
valutum1_.KjopKurs as KjopKurs191_1_,
valutum1_.CultureName as Culture17_191_1_,
valutum1_.TallKode3 as TallKode18_191_1_,
valutum1_.ValutaTabellID as ValutaT19_191_1_
from ValutaHistory valutahist0_
left outer join Valuta valutum1_
on valutahist0_.ValutaID = valutum1_.ValutaID
order by valutahist0_.ValutaHistoryID desc
Obviously WHERE clause is just missing, how is this possible?
Well, when you put a condition on the left side of a left join (your where clause), you essentially nullify the left join (for related tables).
The left join is there to return records from the right side even if there is no match on the left. However, when you put a condition on the left table, you effectively have an inner join.
I'm not sure, but I suspect that NHibernate is detecting this, and deciding that your OrderBy() and First() clauses take precedence over the Where() clause.
So I would turn this query around. Query on, and filter on, the parent entity Valutum, then Fetch the child ValutaHistory and sort.
var pc = _session.Query<Valutum>()
.Where(x => x.ValutaBetegn == updateLine.ProductCurrency)
.FetchMany(x => x.ValutaHistory)
.OrderByDescending(x => x.ValutaHistoryID)
.First();
This works
var pc = _session.Query<ValutaHistory>()
.Where(x => x.Valutum.ValutaBetegn == updateLine.ProductCurrency)
.OrderByDescending(x => x.ValutaHistoryID)
.Fetch(x => x.Valutum)
.First();
Related
I need help converting this sql query into QueryOver Nhibernate criteria.
select distinct * from event e where e.name like '%req%'
or e.Id in (select r.eventId from requirement r where r.name like '%req%')
or e.Id in (select r.eventId from requirement r where r.id
in (select s.requirementId from solution s where s.name like '%sol%'))
var queryOver = session.QueryOver<Event>()
.Where(x => x.Name.IsInsensitiveLike("%"+searchTerms[1]+"%"))
.OrderBy(x => x.CreatedOn).Asc;
So far I have the main query but couldn't find enough reference material on how to add the subqueries. Haven't been successful using joinQueryOver.
Event has one-to-many rel with requirement and requirement has one-to-many rel with solution.
Requirement reqAlias = null;
Solution solAlias = null;
var subQuery = QueryOver.Of<Event>()
.JoinAlias(x => x.Requirements, () => reqAlias)
.Where(x => x.Name.IsInsensitiveLike(searchTerms[2]))
.JoinAlias(() => reqAlias.Solutions, () => solAlias)
.Where(x => x.Name.IsInsensitiveLike(searchTerms[3]))
.Select(Projections.Group<Event>(x => x.Id));
var events = session.QueryOver<Event>()
.Where(x => x.Name.IsInsensitiveLike(searchTerms[1]))
.WithSubquery.WhereProperty(x => x.Id).In(subQuery)
.List().ToList();
still not working.
When you use IsInsensitiveLike NHibernate appends the % after parsing, and uses lower to do a lower case comparison. In your code, you are appending the % yourself, which results in,
select distinct * from event e where e.name like %lower('%req%')%
which in turn, doesn't work.
Also, you have 3 subqueries, no a big one, so you need to restructure your code to account for that:
select r.eventId from requirement r where r.name like '%req%'
to
var firstQuery = QueryOver.Of<Requirement>()
.Where(r => r.Name.IsInsensitiveLike(searchTerms[2]))
.Select(r => r.EventId);
then,
select s.requirementId from solution s where s.name like '%sol%'
to
var solutionQuery = QueryOver.Of<Solution>()
.Where(s => s.Name.IsInsensitiveLike(searchTerms[3]));
then,
select r.eventId from requirement r where r.id
in (select s.requirementId from solution s where s.name like '%sol%')
to
var requirementQuery = QueryOver.Of<Requirement>()
.WithSubquery
.WhereProperty(r => r.Id).In(solutionQuery)
.Select(r => r.EventId);
Then you need to construct the main query using Restrictions.Or to include the 3 queries.
I am having issues getting Nhibernate 3.3.2.4000 to generate the correct subquery used in the orderby clause as displayed below:
select *
from dbo.Person p inner join dbo.Task t on p.Task_FK = p.TaskId
order by (select p.CustomerNumber where p.IsMain=1) desc
We have two entities: Task and Person
One task can have N persons related to it. I.e Task has an IList property.
How can I make Nhibernate generate the correct subquery ? I have gotten as far as something like this with the Query API:
query = query.OrderBy(x => x.Persons.Single(t => t.CustomerNumber));
but I am unsure how I can correctly generate the where clause as displayed in the original sql query. Is this perhaps easier done using the queryover api somehow?
Any advice or guidance is most welcome.
Task task = null
Person person = null;
var subquery = QueryOver.Of<Task>()
.Where(t => t.Id == task.Id)
.JoinQueryOver(t => t.Persons, () => person)
.Where(p => p.IsMain)
.Select(() => person.CustomerNumber);
var query = session.QueryOver(() => task)
.OrderBy(Projections.SubQuery(subquery))
.FetchMany(x => x.Persons)
return query.List();
Basically I crossed the same problem of Linq provider in this linq-to-nhibernate-produces-unnecessary-joins
List<Competitions> dtoCompetitions;
dtoCompetitions = (from compset in session.Query<FWBCompetitionSet>()
where compset.HeadLine == true
&& compset.A.B.CurrentSeason == true
select (new Competitions
{
CompetitionSetID = compset.CompetitionSetID,
Name = compset.Name,
Description = compset.Description,
Area = compset.Area,
Type = compset.Type,
CurrentSeason = compset.A.B.CurrentSeason,
StartDate = compset.StartDate
}
)).ToList();
Which leads to duplicated join in its generated SQL
SELECT fwbcompeti0_.competitionsetid AS col_0_0_,
fwbcompeti0_.name AS col_1_0_,
fwbcompeti0_.DESCRIPTION AS col_2_0_,
fwbcompeti0_.area AS col_3_0_,
fwbcompeti0_.TYPE AS col_4_0_,
fwbseason3_.currentseason AS col_5_0_,
fwbcompeti0_.startdate AS col_6_0_
FROM fwbcompetitionset fwbcompeti0_
INNER JOIN A fwbcompeti1_
ON fwbcompeti0_.competitionseasonid = fwbcompeti1_.competitionseasonid
INNER JOIN A fwbcompeti2_
ON fwbcompeti0_.competitionseasonid = fwbcompeti2_.competitionseasonid
INNER JOIN B fwbseason3_
ON fwbcompeti2_.seasonid = fwbseason3_.seasonid
WHERE fwbcompeti0_.headline = #p0
AND fwbseason3_.currentseason = #p1
Notice these joins, which are totally duplicated and also affect my SQL Server's performence.
INNER JOIN A fwbcompeti1_
ON fwbcompeti0_.competitionseasonid = fwbcompeti1_.competitionseasonid
INNER JOIN A fwbcompeti2_
ON fwbcompeti0_.competitionseasonid = fwbcompeti2_.competitionseasonid
Update1
In the NHibernate 3.2, this LiNQ bug is still valid, and I could not find a simple and reasonable Linq solution.
So I used QueryOver + JoinAlias + TransformUsing finishing the job, workds perfect to me.
FWBCompetitionSet compset = null;
FWBCompetitionSeason compseason = null;
FWBSeason season = null;
IList<Competitions> dtoCompetitions;
dtoCompetitions = session.QueryOver<FWBCompetitionSet>(() => compset)
.JoinAlias(() => compset.FWBCompetitionSeason, () => compseason)
.JoinAlias(() => compseason.FWBSeason, () => season)
.Where(() => compset.HeadLine == true)
.And(() => season.CurrentSeason == true)
.SelectList(
list => list
.Select(c => c.CompetitionSetID).WithAlias(() => compset.CompetitionSetID)
.Select(c => c.Name).WithAlias(() => compset.Name)
.Select(c => c.Description).WithAlias(() => compset.Description)
.Select(c => c.Area).WithAlias(() => compset.Area)
.Select(c => c.Type).WithAlias(() => compset.Type)
.Select(c => season.CurrentSeason).WithAlias(() => season.CurrentSeason)
.Select(c => c.StartDate).WithAlias(() => compset.StartDate)
)
.TransformUsing(Transformers.AliasToBean<Competitions>())
.List<Competitions>();
Yet Another Edit:
I think I finally found out what's going on. It seems that the LINQ to NHibernate provider has trouble navigating associations from the target to the source table and generates a separate join each time it encounters such an association.
Since you don't provide your mapping, I used the mapping from linq-to-nhibernate-produces-unnecessary-joins. This model has a Document with one Job and many TranslationUnits. Each TranslationUnit has many Translation entities.
When you try to find a Translation based on a Job, you are traversing the associations in the reverse order and the LINQ provider generates multiple joins: one for Translation -> TranslationUnit and one for TranslationUnit to Document.
This query will generate redundant joins:
session.Query<TmTranslation>()
.Where(x => x.TranslationUnit.Document.Job == job)
.OrderBy(x => x.Id)
.ToList();
If you reverse the navigation order to Document -> TranslationUnit -> Translation, you get a query that doesn't produce any redundant joins:
var items=(from doc in session.Query<Document>()
from tu in doc.TranslationUnits
from translation in tu.Translations
where doc.Job ==job
orderby translation.Id
select translation).ToList();
Given this quirkiness, QueryOver seems like a better option.
Previous Edit:
I suspect the culprit is compset.A.B.CurrentSeason. The first joined table (fwbcompeti1_) returns A.B while the next two (fwbcompeti2_ and fwbseason3_) are used to return A.B. The LINQ to NHibernate provider doesn't seem to guess that A is not used anywhere else and fails to remove it from the generated statement.
Try to help the optimizer a little by replacing CurrentSeason = compset.A.B.CurrentSeason with CurrentSeason = true from the select, since your where statement returns only items with CurrentSeason == true.
EDIT: What I mean is to change the query like this:
List<Competitions> dtoCompetitions;
dtoCompetitions = (from compset in session.Query<FWBCompetitionSet>()
where compset.HeadLine == true
&& compset.A.B.CurrentSeason == true
select (new Competitions
{
CompetitionSetID = compset.CompetitionSetID,
Name = compset.Name,
Description = compset.Description,
Area = compset.Area,
Type = compset.Type,
CurrentSeason = true,
StartDate = compset.StartDate
}
)).ToList();
I simply replace the value compset.A.B.CurrentSeason with true
BACKGROUND:
Given 3 tables
results contains 2 columns vId and pId
vTable contains 2 columns vId and data
pTable contains 2 columns pId and data
I want to accomplish this sort of SQL query using QueryOver
SELECT v.data, p.data
from results r
inner join vTable v on r.vId = v.vId
inner join pTable p on r.pId = p.pId
I've tried the following:
var res = GetResults(some parameters)
.Select(x => x.vId
.Select(x => x.pID);
var dataset = session.QueryOver<vTable>()
.WithSubquery.WhereProperty(v => v.vId).In(res)
.Select(v => v.vId)
.Select(v => v.data)
which works just fine to get data from vTable
however, when I add the 2nd table
var dataset = session.QueryOver<vTable>()
.WithSubquery.WhereProperty(v => v.vId).In(res)
.JoinQueryOver<pTable>(p => p.pId)
.WithSubquery.WhereProperty(p => p.pId).In(res)
.Select(v => v.vId)
.Select(v => v.data)
.Select(p => p.pId)
.Select(p => p.data)
I get the error
Delegate 'System.Func<System.Collections.Generic.IEnumerable<pTable>>' does not take 1 arguments
What am I doing wrong?
.JoinQueryOver<pTable>(p => p.pId)
has to point to a mapped entity or collection not it an id, if you can't map it in the hbm. And also the JoinQueryOver will return pTables not vTables, you might want to use JoinAlias instead if you wan to retain the return type to be a list of vTables, but if all you want is that projection make sure you add aliases the QueryOver and JoinQueryOver calls
I have Entity 'Content'. Each Content has a 'Placement' property. Placement has a many-to-many relationship width 'AdType' entity (Placement has IList<\AdType> property mapped).
I need to load all Placements that are used at least in one Content and associated width specified AdType.
My DAL function looks like this:
public IList<Placement> Load(AdType adType)
{
return NHibernateSession.QueryOver<Content>()
.JoinQueryOver(content => content.Placement)
.JoinQueryOver<AdType>(placement => placement.AdTypes)
.Where(_adType => _adType.Id == adType.Id)
.Select(x => x.Placement).List<Placement>();
}
This works fine but when I look to the SQL log i see:
SELECT this_.PlacementId as y0_ FROM AdManager.dbo.[Content] this_ inner join AdManager.dbo.[Placement] placement1_ on this_.PlacementId=placement1_.PlacementId inner join AdManager.dbo.AdTypeToPlacement adtypes5_ on placement1_.PlacementId=adtypes5_.PlacementId inner join AdManager.dbo.[AdType] adtype2_ on adtypes5_.AdTypeId=adtype2_.AdTypeId WHERE adtype2_.AdTypeId = #p0
SELECT placement0_.PlacementId as Placemen1_26_0_, placement0_.Name as Name26_0_ FROM AdManager.dbo.[Placement] placement0_ WHERE placement0_.PlacementId=#p0
SELECT placement0_.PlacementId as Placemen1_26_0_, placement0_.Name as Name26_0_ FROM AdManager.dbo.[Placement] placement0_ WHERE placement0_.PlacementId=#p0
This means that NHibernate takes all placements Id in first query and then queries all fields from Placement table by Id.
My question is: Does enyone know how to modify QueryOver method to force NHibernate load data in one query?
it seems NHibernate does think there might be something in the where which maybe filters out data which is needed tro initialize the placement. You can go with a subquery:
public IList<Placement> Load(AdType adType)
{
var subquery = QueryOver.For<Content>()
.JoinQueryOver(content => content.Placement)
.JoinQueryOver<AdType>(placement => placement.AdTypes)
.Where(_adType => _adType.Id == adType.Id)
.Select(x => x.Id);
return NHibernateSession.QueryOver<Content>()
.WithSubquery.Where(content => content.Id).IsIn(subquery))
//.Fetch(x => x.Placement).Eager try with and without
.Select(x => x.Placement).List<Placement>();
}
or SQL (has the disadvantage that it just fills the new Placement but doest track it)
public IList<Placement> Load(AdType adType)
{
return NHibernateSession.CreateSQLQuery("SELECT p.Name as Name, ... FROM content c join placement p...")
.SetResultTransformer(Transformers.AliastoBean<Placement>())
.List<Placement>();
}