Cannot execute query against cache
Printed From: IdeaBlade
Category: DevForce
Forum Name: DevForce 2010
Forum Discription: For .NET 4.0
URL: http://www.ideablade.com/forum/forum_posts.asp?TID=1763
Printed Date: 21-Apr-2026 at 7:23am
Topic: Cannot execute query against cache
Posted By: JeeZ
Subject: Cannot execute query against cache
Date Posted: 27-Apr-2010 at 6:44pm
Hi everybody,
Here's the query I'm trying to execute :
query = _manager.Customers.Where(p =>
p.CompanyName.Contains(_searchKeyword)
||
p.ContactName.Contains(_searchKeyword)
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p.ContactTitle.Contains(_searchKeyword)
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p.City.Contains(_searchKeyword)
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p.Country.Contains(_searchKeyword)
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p.Region.Contains(_searchKeyword)
||
p.Phone.Contains(_searchKeyword)
||
p.Fax.Contains(_searchKeyword)
); |
Here's the exception :
Execution of query against the server was successful but execution of query against the local cache failed |
Why?
Note: In a C# WinForm Application, on NorthwindIB database, DevForce Universal Express.
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Replies:
Posted By: ting
Date Posted: 29-Apr-2010 at 5:26pm
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That should work. We're going to run some tests and will let you know what we find.
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Posted By: GregD
Date Posted: 29-Apr-2010 at 6:54pm
Originally posted by JeeZ
query = _manager.Customers.Where(p =>
p.CompanyName.Contains(_searchKeyword)
||
p.ContactName.Contains(_searchKeyword)
||
p.ContactTitle.Contains(_searchKeyword)
||
p.City.Contains(_searchKeyword)
||
p.Country.Contains(_searchKeyword)
||
p.Region.Contains(_searchKeyword)
||
p.Phone.Contains(_searchKeyword)
||
p.Fax.Contains(_searchKeyword)
);
|
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Nice that you were using the NorthwindIB database: that made debugging this a bunch easier, since I have not only the same schema but virtually the same data to test with.
Your query fails because the columns Region and Fax have nulls in them, and .Contains() isn't defined on a null in LINQ. (The query against the server succeeds because EF translates it to SQL that works.)
If your copy of NorthwindIB is like mine, you'll also find two records that have nulls in some of the other columns besides Region and Fax; but those two records have nulls in all of the columns on which you're doing the test, so they don't meet the condition you've posed and are never brought down to the client. Therefore they don't cause the query to fail when it's run on the client!
THE FIX
You can make your query work by changing the syntax of your tests to the following:
(p.Region ?? "").Contains(_searchKeyword)
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That converts any null to an empty string before executing the Contains test.
As it so happens, we had already changed DevForce (I now know) to do the above translation automatically; so as of the next release, the syntax you used to begin with will work. But you'll need the above syntax for now.
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Posted By: JeeZ
Date Posted: 30-Apr-2010 at 4:31am
Thanks Greg! I'll try that and get back to you next week if it doesn't work (but I'm confident it will).
Have a nice week-end!
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