Raven DB gave me this message
Method not supported: Contains
for this code :
using (var d = DataLayer.RavenDB.d.OpenSession())
{
foos = d.Query<Foo>().Where(foo => ids.Contains(foo.Id)).Skip(i * 10).Take(10).ToList();
}
how can I retrieve my list foos ?
It looks like you are trying to query multiple documents by id. Querying by Id is not recommended in Raven. Load them instead. There is an overload that takes multiple Ids.
foos = session.Load<Foo>(ids);
If this was some other property rather than Id, you would use item.In(list) rather than list.Contains(item).
if you want to load the documents based on the list of ids, go the solution suggested by Matt, performance wise Load() is the best approach.
but if you still wants to get it using Query (using some where contiions) change the code like this
using (var d = DataLayer.RavenDB.d.OpenSession())
{
foos = d.Query<Foo>()
.Where(foo => foo.Id.In<string>(ids))
.Skip(i * 10)
.Take(10).ToList();
}
Related
I am integrating FOSElasticaBundle in my Symfony 2.3 project and I need to sort the results by their price property.
Here is my code:
$finder = $this->container->get('fos_elastica.finder.website.product');
$fieldTerms = new \Elastica\Query\Terms();
$fieldTerms->setTerms('taxon_ids', $taxon_ids_array);
$boolQuery->addMust($fieldTerms);
$resultSet = $finder->find($boolQuery);
How I can do this?
Thanks
Try create a \Elastica\Query object which also contains the sorting information, then send this to the finder:
$finder = $this->container->get('fos_elastica.finder.website.product');
$fieldTerms = new \Elastica\Query\Terms();
$fieldTerms->setTerms('taxon_ids', $taxon_ids_array);
$boolQuery->addMust($fieldTerms);
$finalQuery = new \Elastica\Query($boolQuery);
$finalQuery->setSort(array('price' => array('order' => 'asc')));
$resultSet = $finder->find($finalQuery);
Have a look at the elasticsearch docs on the sort parameter to see how to use it properly.
NOTE: \Elastica\Query is quite different to \Elastica\Query\AbstractQuery, the first encapsulates everything you could send to the _search API endpoint (facets, sorting, explain, etc...) The AbstractQuery represents a base type for each of the individual query types (range, fuzzy, terms, etc...).
I have an Abstract type called Product, and five "Types" that inherit from Product in a table per type hierarchy fashion as below:
I want to get all of the information for all of the Products, including a smattering of properties from the different objects that inherit from products to project them into a new class for use in an MVC web page. My linq query is below:
//Return the required products
var model = from p in Product.Products
where p.archive == false && ((Prod_ID == 0) || (p.ID == Prod_ID))
select new SearchViewModel
{
ID = p.ID,
lend_name = p.Lender.lend_name,
pDes_rate = p.pDes_rate,
pDes_details = p.pDes_details,
pDes_totTerm = p.pDes_totTerm,
pDes_APR = p.pDes_APR,
pDes_revDesc = p.pDes_revDesc,
pMax_desc = p.pMax_desc,
dDipNeeded = p.dDipNeeded,
dAppNeeded = p.dAppNeeded,
CalcFields = new DAL.SearchCalcFields
{
pDes_type = p.pDes_type,
pDes_rate = p.pDes_rate,
pTFi_fixedRate = p.pTFi_fixedRate
}
}
The problem I have is accessing the p.pTFi_fixedRate, this is not returned with the Products collection of entities as it is in the super type of Fixed. How do I return the "super" type of Products (Fixed) properties using Linq and the Entity Framework. I actually need to return some fields from all the different supertypes (Disc, Track, etc) for use in calculations. Should I return these as separate Linq queries checking the type of "Product" that is returned?
This is a really good question. I've had a look in the Julie Lerman book and scouted around the internet and I can't see an elegant answer.
If it were me I would create a data transfer object will all the properties of the types and then have a separate query for each type and then union them all up. I would insert blanks into the DTO properies where the properties aren't relevant to that type. Then I would hope that the EF engine makes a reasonable stab at creating decent SQL.
Example
var results = (from p in context.Products.OfType<Disc>
select new ProductDTO {basefield1 = p.val1, discField=p.val2, fixedField=""})
.Union(
from p in context.Products.OfType<Fixed>
select new ProductDTO {basefield1 = p.val1, discField="", fixedField=p.val2});
But that can't be the best answer can it. Is there any others?
So Fixed is inherited from Product? If so, you should probably be querying for Fixed instead, and the Product properties will be pulled into it.
If you are just doing calculations and getting some totals or something, you might want to look at using a stored procedure. It will amount to fewer database calls and allow for much faster execution.
Well it depends on your model, but usually you need to do something like:
var model = from p in Product.Products.Include("SomeNavProperty")
.... (rest of query)
Where SomeNavProperty is the entity type that loads pTFi_fixedRate.
How would I modify the following code:
var result = from p in Cache.Model.Products
from f in p.Flavours
where f.FlavourID == "012541-5-5-5-651"
select p;
So that f.FlavourID is supplied a range of ID's as a supposed to just one value as shown in the above example?
Given the following ERD Model:
Products* => ProdCombinations <= *Flavours
ProdCombinations is a junction/link table and simply has one composite key in there.
Of the top of my head
string [] ids = new[]{"012541-5-5-5-651", "012541-5-5-5-652", "012541-5-5-5-653"};
var result = from p in Cache.Model.Products
from f in p.Flavours
where ids.Contains(f.FlavourID)
select p;
There are some limitations, but an array of ids has worked for me before. I've only actually tried with SQL Server backend, and my IDs were integers.
As I understand it, Linq needs to translate your query into SQL, and it's only possible sometimes. For example it's not possible with IEnumerable<SomeClass>, which produces a runtime error, but possible with a collection of simple types.
I have a db model with the following tables:
A * ---- 1 B 1 ---- * C
Based on this schema I have created a Entity Data Model which allows me to load all the As in my DB. As I also use the Bs in my Linq queries I load the As like this:
using(MyEntities entities = new MyEntities()){
var result = from a in entities.As.Include("B") where a.Code == 123 && a.B.Code == 321 select a;
}
The results can be further filtered by the user so I am building filters depending on the user's selection like this:
int filterValue = 222; //FilterValue is passed in by the user
IList<Func<A, bool>> filters = new List<Func<A, bool>>();
filters.Add(x => x.B.C.Any(i => i.C.Code == filterValue));
...build more filters...
Later on I apply the filters using:
foreach (var filter in filters)
{
results = results.Where(filter);
}
Notice that in the filter code I'm using C reference (which is a collection of Cs). That's where EF fails because the C collection is empty (has not be loaded). How can I force EF to eagerly load all related properties for an object graph so I can apply my filters or is there a better way of doing this?
Thanks.
The reason why your C is not loaded is because you are not including it in your query. You must use:
entities.As.Include("B.C")
But the result is as described by #Eranga - you are transferring all records to your application and filters them in your application memory by linq-to-objects instead of doing filtering by linq-to-entities and transferring only filtered records.
You are using IList<Func<A, bool>> as filters. This makes it a LINQ-to-Objects query. Thats why you are complaining C collection is empty.
So instead use IList<Expression<Func<A, bool>>> as filters.
Ok this should be really simple, but I am doing my head in here and have read all the articles on this and tried a variety of things, but no luck.
I have 3 tables in a classic many-to-many setup.
ITEMS
ItemID
Description
ITEMFEATURES
ItemID
FeatureID
FEATURES
FeatureID
Description
Now I have a search interface where you can select any number of Features (checkboxes).
I get them all nicely as an int[] called SearchFeatures.
I simply want to find the Items which have the Features that are contained in the SearchFeatures.
E.g. something like:
return db.Items.Where(x => SearchFeatures.Contains(x.ItemFeatures.AllFeatures().FeatureID))
Inside my Items partial class I have added a custom method Features() which simply returns all Features for that Item, but I still can't seem to integrate that in any usable way into the main LINQ query.
Grr, it's gotta be simple, such a 1 second task in SQL. Many thanks.
The following query will return the list of items based on the list of searchFeatures:
from itemFeature in db.ItemFeatures
where searchFeatures.Contains(itemFeature.FeatureID)
select itemFeature.Item;
The trick here is to start with the ItemFeatures table.
It is possible to search items that have ALL features, as you asked in the comments. The trick here is to dynamically build up the query. See here:
var itemFeatures = db.ItemFeatures;
foreach (var temp in searchFeatures)
{
// You will need this extra variable. This is C# magic ;-).
var searchFeature = temp;
// Wrap the collection with a filter
itemFeatures =
from itemFeature in itemFeatures
where itemFeature.FeatureID == searchFeature
select itemFeature;
}
var items =
from itemFeature in itemFeatures
select itemFeature.Item;