DevForce Community Forum : Devforce Queries and IQueryable<T>.Count() http://www.ideablade.com/forum/ This is an XML content feed of; DevForce Community Forum : DevForce 2009 : Devforce Queries and IQueryable<T>.Count() Sat, 11 Apr 2026 22:19:04 -700 Tue, 26 May 2009 11:03:39 -700 http://blogs.law.harvard.edu/tech/rss Web Wiz Forums 9.69 360 www.ideablade.com/forum/RSS_post_feed.asp?TID=1280 DevForce Community Forum http://www.ideablade.com/forum/forum_images/IdeaBlade_logo_tm.png http://www.ideablade.com/forum/ Devforce Queries and IQueryable<T>.Count() : This behavior is by design. An... http://www.ideablade.com/forum/forum_posts.asp?TID=1280&PID=4643#4643 Author: kimj
Subject: 1280
Posted: 26-May-2009 at 11:03am

This behavior is by design.   An "immediate execution" type of query (such as Count(), Max(), First()) which returns a number or other scalar can only be meaningfully executed against cache or the data source, but not a combination.  In this case if we tried the usual DataSourceThenCache behavior and, for example, found 77 in the database and 78 in cache, what would the union of these two numbers mean?   When the QueryStrategy is "Normal" queries such as this actually resolve to using a DataSourceOnly fetch strategy. 
 
The "Ex03_ExploringFetchStrategies.docx" in the Fundamentals series of Learning Units has a discussion on this topic.
]]> Tue, 26 May 2009 11:03:39 -700 http://www.ideablade.com/forum/forum_posts.asp?TID=1280&PID=4643#4643 Devforce Queries and IQueryable<T>.Count() : Hi, We are using Devforce 5.1... http://www.ideablade.com/forum/forum_posts.asp?TID=1280&PID=4639#4639 Author: jozza
Subject: 1280
Posted: 25-May-2009 at 6:14pm

Hi,

We are using Devforce 5.1 and I've come across an issue where IQueryable<T>.Count() seems to return only the count of entities that are actually in the database and does not include the ones that have been newly created and are still in the cache.

As an example I have used Northwind and the Product table.

Facade facade = new Facade();

DomainModel.DomainModelEntityManager mgr = new DomainModel.DomainModelEntityManager();
 
int count = facade.GetProducts(mgr).Count<DomainModel.Product>();  <=== This returns 77
 
DomainModel.Product p = DomainModel.Product.Create(mgr, 9000, "Test"); <=== We create a new product
 
count = facade.GetProducts(mgr).Count<DomainModel.Product>(); <=== This still returns 77
 
List<DomainModel.Product> l = facade.GetProducts(mgr).ToList<DomainModel.Product>(); <== We convert it to List
 
count = l.Count<DomainModel.Product>(); <==== Now the count has 78
 
 
The only way I have been able to get the correct count of items in my entity set is to convert the IQueryable results to a List, and then get a count.
 
Is this a bug? or something done by design? If so, what was the rationale behind it?
 
Cheers
 
Jacob Jozwiak
 
 
]]> Mon, 25 May 2009 18:14:07 -700 http://www.ideablade.com/forum/forum_posts.asp?TID=1280&PID=4639#4639