I've been looking for a week after a correct synthax whithout success.
I have 2 classes :
public class ArtworkData
{
public virtual Guid Id { get; set; }
public virtual string Name { get; set; }
public virtual IList<CommentData> Comments { get; set; }
}
public class CommentData
{
public virtual Guid Id { get; set; }
public virtual string Text { get; set; }
public virtual ProfileData Profile { get; set; }
public virtual ArtworkData Artwork { get; set; }
public virtual DateTime Created { get; set; }
}
I want to do this query :
SELECT this_.ArtworkId as ArtworkId3_3_,
this_.Name as Name3_3_,
this_.Description as Descript3_3_3_,
FROM Artwork this_
LEFT outer JOIN
(SELECT c.ArtworkIdFk, count(1) Cnt
FROM Comment c
GROUP BY c.ArtworkIdFk) as com
on com.ArtworkIdFk = this_.ArtworkId
ORDER BY 1 desc
But I don't find the way to.
At this moment I just have something like this :
ICriteria c = this.Session.CreateCriteria(typeof(ArtworkData));
if(filter.Category !=null)
{
c.CreateAlias("Categories", "cat")
.Add(Restrictions.Eq("cat.Id", filter.Category.Id));
}
DetachedCriteria crit = DetachedCriteria.For(typeof(CommentData), "comment")
.SetProjection(Projections.ProjectionList()
.Add(Projections.Count("comment.Id").As("cnt"))
.Add(Projections.GroupProperty("comment.Artwork.Id")));
c.Add(Expression.Gt(Projections.SubQuery(crit), 0));
c.AddOrder(Order.Desc(Projections.SubQuery(crit)));
But it's not what I want.
I want to get all Artworks order by the number of comments (but I don't need to get this number).
Please help me! I'm going crazy!
I don't understand what are you trying to do with this weird SQL but if you need to get all Artworks with number of comments you can try this query:
<query name="ArtworkWithCommentsCount">
SELECT artwork.Name, artwork.Comments.size
FROM Artwork artwork
</query>
If you use NHibernate 3 you could use this code:
var artworks = Session.Query<Artwork>().OrderBy(a => Comments.Count);
Or you could use HQL:
Session.CreateQuery("from Artwork a order by size(a.Comments)")
Try Detached Criteria. Take a look at this blogpost.
Related
After trying numerous things, I am still unable to figure out the right way to query the following relationship using Fluent NHibernate.
This would otherwise have been an easier task if I had to write SQL queries. Hope to get some better advice to avoid N+1 issue and unoptimized auto-generated SQL queries.
I have the following relationship which goes something as below :
Tags can have media content (Images of various predefined sizes, videos, documents etc.) associated with it.
- 1 Tags can have multiple Media Items mapped to it (Lets's say images with dimension 32x32, 64x64, 600x100, 0 or more Videos)
- Every media item is mapped to a media description which helps in identifying the size and type of the media
- The same media item can be used by a different tag. Example, having a generic image for all tags which do not have any icons.
Entities:
Media
public class Media:IEntity
{
private ICollection<TagMedia> _tagMedia;
public virtual int Id { get; set; }
public virtual string FilePath { get; set; }
public virtual MediaType MediaType { get; set; }
public virtual ICollection<TagMedia> TagMedia
{
get { return _tagMedia?? (_tagMedia= new List<TagMedia>()); }
protected set { _tagMedia= value; }
}
}
Tag
public class Tag:IEntity
{
private ICollection<TagMedia> _tagMedia;
public virtual int Id { get; set; }
public virtual string Name { get; set; }
public virtual ICollection<TagMedia> TagMedia
{
get { return _tagMedia?? (_tagMedia= new List<TagMedia>()); }
set { _tagMedia= value; }
}
}
TagMedia
public class TagMedia :IEntity
{
public virtual int Id { get; set; }
public virtual Media Media { get; set; }
public virtual Tag Tag { get; set; }
public virtual DateTime AddedOn { get; set; }
}
MediaType
public class MediaType:IEntity
{
public virtual int Id { get; set; }
public virtual string Description { get; set; }
}
Mappings
MediaMapping
public class MediaMapping : IAutoMappingOverride<Media>
{
public void Override(AutoMapping<Media> mapping)
{
mapping.Map(c => c.FileName).CustomSqlType("varchar(60)").Not.Nullable();
}
}
TagMapping
public class TagMapping : IAutoMappingOverride<Tag>
{
public void Override(AutoMapping<Tag> mapping)
{
mapping.HasMany<TagMedia>(c => c.TagMedia)
.KeyColumn("TagId")
.Cascade.SaveUpdate()
.BatchSize(25);
mapping.BatchSize(25);
mapping.DynamicUpdate();
mapping.DynamicInsert();
}
}
TagMediaMapping
public class TagMediaMapping : IAutoMappingOverride<TagMedia>
{
public void Override(AutoMapping<TagMedia> mapping)
{
mapping.Map(c=>c.AddedOn);
}
}
Query:
The following query gets the cartesian product of all media mapped to the tag and does not eliminate records other than "Icon-16x16". I expect the ORM to return no more than one row.
Any help would be highly appreciated.
_session.Query<Tag>()
.FetchMany(x => x.TagMedia)
.ThenFetch(x => x.Media)
.ThenFetch(x=>x.MediaType)
.Where(c => c.Id == id
&& c.TaxonomyMedia.Any(x=>x.Media.MediaType.Description== "Icon-16x16"))
.SingleOrDefault();
Generated SQL:
exec sp_executesql N'select *
from [Tag] Tag0_ left outer join [TagMedia] Tagme1_ on Tag0_.TagId=Tagme1_.TagId
left outer join [Media] media2_ on Tagme1_.MediaId=media2_.MediaId
left outer join [MediaType] mediatype3_ on media2_.MediaTypeId=mediatype3_.MediaTypeId
where Tag0_.TagId=#p0
and (exists (select Tagme4_.TagMediaId
from [TagMedia] Tagme4_ inner join [Media] media5_ on Tagme4_.MediaId=media5_.MediaId inner join [MediaType] mediatype6_ on media5_.MediaTypeId=mediatype6_.MediaTypeId where Tag0_.TagId=Tagme4_.TagId and mediatype6_.MediaTypeDescription=#p1))',N'#p0 int,#p1 nvarchar(4000)',#p0=102,#p1=N'Icon-16x16'
go
the SingleOrDefault function is a LINQ function and not implemented by NHibernate. Use .Take(1)
I think the solution is:
_session.Query<Tag>()
.FetchMany(x => x.TagMedia)
.ThenFetch(x => x.Media)
.ThenFetch(x=>x.MediaType)
.Where(c => c.Id == id
&& c.TaxonomyMedia.Any(x=>x.Media.MediaType.Description== "Icon-16x16"))
.Take(1)
.SingleOrDefault();
I am trying to select from a list of categories where it matches the category type of a list of items using linq. IE, from a list of all the FIGstationeryCategories, select only the ones where the FiGStationeryType has a matching category from an already filtered list. The models are listed below.
public class FIGstationeryType
{
public int Id { get; set; }
public virtual FIGstationeryCategory Category { get; set; }
public virtual FIGcompany Company { get; set; }
public decimal Height { get; set; }
public decimal Width { get; set; }
public virtual FIGstationeryType Template { get; set; }
public bool DoubleSided { get; set; }
}
public class FIGstationeryCategory
{
public int Id { get; set; }
public string Name { get; set; }
public decimal MaxZoom { get; set; }
public ICollection<FIGstationeryType> StationeryItems { get; set; }
}
I have been going around in circles with this, and any help will be much appreciated. I haven't got very far! The first line of code works fine, it is the second one I am struggling with.
var listOfItems = db.StationeryTypes
.Where(C => C.Company.Users.Any(u => u.UserId == WebSecurity.CurrentUserId))
.ToList();
var categoryList = db.StationeryCategories
.Where(listOfItems
Any help would be much appreciated.
var listOfCategories =
(from o in listOfItems select o.Category.Name).Distinct().ToList();
When I thought about it (After watching 3 hours of linq videos last night), I realised that the listOfItems already held all the categories which where in use, so I didn't need to query and compare the two tables, just draw the relevant values from the list I already had.
I am not entirely sure how you want to select your categories but this probably goes a little way:
var categoryList = db.StationeryCategories
.*Select*(x => listOfItems.Where(y => y.Category == x)
.FirstOrDefault());
Can you clarify if this is the criteria you are after?
How do you do this query in NHibernate, with criteria or QueryOver?
select r.relationshipidentifier, r.publicrelationshipid
from relationship r
inner join (
select max(asofdate) as asofdate, s.relationshipidentifier
from relationship s
group by s.relationshipidentifier
) m
on r.asofdate = m.asofdate and r.relationshipidentifier = m.relationshipidentifier
Assume
public class Relationship {
public virtual Guid Id { get; set; }
public virtual DateTime AsOfDate { get; set; }
public virtual Guid RelationshipIdentifier { get; set; }
public virtual Guid PublicRelationshpId { get; set; }
}
the inner join can be described by a subquery.
something to the effect of -
QueryOver.Of<Relationship>()
.SelectList(list =>
list.SelectMax(r => r.AsOfDate),
list.GroupProperty(r=> r.RelationshipIdentifier)
)
and you can use the WithSubquery method of QueryOver to inner join to that subquery.
see this article for further details on QueryOver API.
I have a ravendb class like such:
public class Student
{
public string Id { get; set; }
public string TopLevelProperty { get; set; }
public Dictionary<string, string> Attributes { get; set; }
public Dictionary<string,List<Dictionary<string, string>>> CategoryAttributes { get; set; }
}
and a document like so:
The following linq will not work due to a selectmany:
test = (from student in session.Query()
from eduhistory in student.CategoryAttributes["EducationHistory"]
where eduhistory["StartYear"] == "2009"
select student).ToList();
How can I get all students where StartYear == 2009?
This does it :
test = session.Advanced.LuceneQuery()
.Where("CategoryAttributes.EducationHistory,StartYear:2009")
.ToList();
Notice the comma rather than a dot after EducationHistory. This indicates that we are looking at the list to find a property in one of the items named StartYear.
If I wanted greater than :
test = session.Advanced.LuceneQuery()
.Where("CategoryAttributes.EducationHistory,StartYear:[2009 TO null]")
.ToList();
etc etc.
This should work:
test = (from student in session.Query()
where student.CategoryAttributes["EducationHistory"].Any(edu => edu["StartYear"]== "2009" )
select student).ToList();
I have the following classes:
public class Item
{
public int Id { get; set; }
public IDictionary<int, ItemLocal> { get; protected set; }
public ICollection<string> Tags { get; set; }
public int DefaultLanguageId { get; set; }
public DateTime Start { get; set; }
}
public class ItemLocal
{
public virtual Item Parent { get; set; }
public virtual int LanguageId { get; set; }
public string Title { get; set; }
public string Description { get; set; }
}
These map to the tables Item, ItemTag and ItemLocal. I want to make the following query via the criteria api:
select
i.Id,
i.Start,
l.Title
from
Item i
left join ItemLocal l on i.Id = l.ParentId and i.DefaultLangaugeId = l.LanguageId
order by
l.Title,
i.Id
But I dont know how to perform the left join with the nhibernate criteria api. Especially with the usage of the default language selection.
Any help is very appreciated.
I have found a solution:
Session
.CreateCriteria<Item>("i")
.CreateCriteria("Localization", "l", NHibernate.SqlCommand.JoinType.LeftOuterJoin)
.Add(Restrictions.Disjunction()
.Add(Restrictions.EqProperty("i.DefaultLanguageId", "l.LanguageId"))
.Add(Restrictions.IsNull("l.LanguageId"))
)
.AddOrder(Order.Asc("l.Title"))
.AddOrder(Order.Asc("w.Id"));
This seems to work but results in a query with a workaround WHERE clause. Would rather see that it could render a SQL query where the restrictions defined in the disjunction could be part of the OUTER LEFT JOIN ... ON ... statement.