I would like to restrict a query using the QueryOver mechanism in Fluent Nhibernat. I found that I can do this using WhereRestrictOn but there seems to be no possibility to compare to just one value. A IsEqual method of sorts.
I quick example might explain better what my issue is
class Parent{
IList<Child1> C1 {get;set;}
IList<Child2> C2 {get;set;}
}
class Child1{
int Id {get;set;}
}
class Child2{
int Id {get;set;}
}
//What I can do
var result = session.QueryOver<Parent>()
.WhereRestrictionOn(x => x.C1.Id).IsIn(new[]{3})
.AndRestrictionOn(x => x.C2.Id).IsIn(new[]{5}).List();
//What I would like to do
var result = session.QueryOver<Parent>()
.WhereRestrictionOn(x => x.C1.Id).IsEqual(3)
.AndRestrictionOn(x => x.C2.Id).IsEqual(5).List();
So basically my issue is that I'm not able to compare with one value but always have to artifically create an array. Is this not possible or am I missing something?
If it is possible please tell me how. If it is not possible I would appreciate an explantion as to why not.
Thanks in advance.
Try this:
Child1 c1Alias = null;
Child2 c2Alias = null;
var result = session.QueryOver<Parent>()
.InnerJoin(x => x.C1, () => c1Alias) // or use Left.JoinAlias
.InnerJoin(x => x.C2, () => c2Alias) // or use Left.JoinAlias
.Where(() => c1Alias.Id == 3)
.And(() => c2Alias.Id == 2)
.List();
I think you want a pair of Subqueries rather than a restriction, but you'll have to map the ParentID value in both Child1 and Child2.
Each SubQuery should return the ParentID where the childID is your search value, and then you can use a conjunction to return the Parent for both children, or null if there isn't one, I suppose.
Related
I have a table message_thread:
id
sender_id
recipient_id
I want to declare a relation in my User model that will fetch all message threads as follows:
SELECT *
FROM message_thread
WHERE sender_id = {user.id}
OR recipent_id = {user.id}
I have tried the following:
public function getMessageThreads()
{
return $this->hasMany(MessageThread::className(), ['sender_id' => 'id'])
->orWhere(['recipient_id' => 'id']);
}
But it generates an AND query. Does anyone know how to do this?
You cannot create regular relation in this way - Yii will not be able to map related records for eager loading, so it not supporting this. You can find some explanation int this answer and related issue on GitHub.
Depending on use case you may try two approach to get something similar:
1. Two regular relations and getter to simplify access
public function getSenderThreads() {
return $this->hasMany(MessageThread::className(), ['sender_id' => 'id']);
}
public function getRecipientThreads() {
return $this->hasMany(MessageThread::className(), ['recipient_id' => 'id']);
}
public function getMessageThreads() {
return array_merge($this->senderThreads, $this->recipientThreads);
}
In this way you have two separate relations for sender and recipient threads, so you can use them directly with joins or eager loading. But you also have getter which will return result ofboth relations, so you can access all threads by $model->messageThreads.
2. Fake relation
public function getMessageThreads()
{
$query = MessageThread::find()
->andWhere([
'or',
['sender_id' => $this->id],
['recipient_id' => $this->id],
]);
$query->multiple = true;
return $query;
}
This is not real relation. You will not be able to use it with eager loading or for joins, but it will fetch all user threads in one query and you still will be able to use it as regular active record relation - $model->getMessageThreads() will return ActiveQuery and $model->messageThreads array of models.
Why orOnCondition() will not work
orOnCondition() and andOnCondition() are for additional ON conditions which will always be appended to base relation condition using AND. So if you have relation defined like this:
$this->hasMany(MessageThread::className(), ['sender_id' => 'id'])
->orOnCondition(['recipient_id' => new Expression('id')])
->orOnCondition(['shared' => 1]);
It will generate condition like this:
sender_id = id AND (recipent_id = id OR shared = 1)
As you can see conditions defined by orOnCondition() are separated from condition from relation defined in hasMany() and they're always joined using AND.
For this query
SELECT *
FROM message_thread
WHERE sender_id = {user.id}
OR recipent_id = {user.id}
You Can use these
$query = (new \yii\db\Query)->from("message_thread")
$query->orFilterWhere(['sender_id'=>$user_id])->orFilterWhere(['recipent_id '=>$user_id]);
I'm struggling with using QueryOver.OrderBy with strings for property names on child entities. e.g. the following works but I am hardcoding the OrderBy field.
Customer custAlias = null;
session.QueryOver<Campaign>()
.JoinAlias(x => x.Customer, () => custAlias)
.OrderBy(() => custAlias.Name).Desc() // want to use string property name
.List();
I can specify the OrderBy using a string with something like:
.OrderBy(Projections.Property("DOB")).Desc();
But this is looking for "DOB" on the Campaign entity, not the child Customer entity. Is it possible to retrieve the alias used by NH and then set the path to the property e.g.
.OrderBy(Projections.Property("cust.DOB")).Desc(); // where "cust" is the alias
Any ideas?
The alias used is the name of the variable. So
Projections.Property("custAlias.DOB")
(can't test now, but if I remember corretly it works)
Interestingly, it isn't the variable, in itself, that is used as the alias, but its name. What does it means?
QueryOver<Campaign> query;
{
Customer custAlias = null;
query = session.QueryOver<Campaign>()
.JoinAlias(x => x.Customer, () => custAlias)
}
{
Customer custAlias = null;
var result = query.OrderBy(() => custAlias.Name).Desc() // want to use string property name
.List()
}
Two different custAlias, but it still works :-)
(useful if you want to split pieces of a query in multiple methods... The only important thing is that they use the same naming for the aliases)
I have 2 entities, linked via a Many to Many called Parent and Child.
In Child I have an IList of Parents,
In Parent I have an IList of Childs.
I am trying to do a query on a list of parents, that is linked to a child.
Conceptually wise, I am looking for something like this:
var Query = session.QueryOver<Parent>()
Query.Where(o => o.Children.Contains(child));
But this won't work, so what ways can I get this to work?
Thanks!
You need to use JoinQueryOver
session.QueryOver<Parent>().JoinQueryOver<Child>(p => p.Childs)
.Where(c => c.Id == child.Id)
var query = session.QueryOver<Parent>()
.Where(o => o.Children.Contains(child));
or
var query = session.Query<Parent>()
.Where(o => o.Children.Contains(child));
or see Vadim
I want to do a sort of filtering chain to filter Receipt objects using queryOver functionality.
The chain can differ in length, according to the parameters user chooses on the screen.
Eventually, I want the chain to run somehow like this:
public IList<Receipt> RunFilters()
{
IQueryOver<Receipt, Receipt> currQuery = NHibernateHelper.Session.QueryOver<Receipt>();
foreach (var item in filters)
{
currQuery = item.RunFilter(currQuery);
}
return currQuery.List();
}
So, the question is - how RunFilter should be defined? I thought it should be
public IQueryOver<Receipt, Receipt> RunFilter(IQueryOver<Receipt, Receipt> prevFilter)
and they I can do filters like
return prevFilter.Where(receipt => receipt.TotalSum > 0);
But I can't do
return prevFilter.JoinQueryOver(v => v.Store).Where(vv => vv.Name.Equals(m_storeName));
Any ideas?
Thanks in advance
Victor
return prevFilter.JoinQueryOver(v => v.Store).Where(vv => vv.Name.Equals(m_storeName));
the above can be written as
Store storeAlias = null;
return prevFilter.JoinAlias(v => v.Store, () => storeAlias).Where(() => storeAlias.Name == m_storeName);
EDIT: fixed equation
I have a question. I have this query:
var query = QueryOver.Of<Item>()
.JoinQueryOver<ItemRelation>(p => p.ItemRelation)
.Where(r => r.Item1.Id == itemId)
How can I return only Item entity but not Item Relation?
Thanks
The query actually should only return Predmet ... The RelacijaPredmeta is a property of it. If you don't want to load it, use lazy loading, or select the properties of Predmet individually.