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Showing posts from 2011

LINQ to Object JOIN

I was reviewing a piece of LINQ to Object Join query of one of my colleagues and a code that is written like this (example, not the exact code, the actual query was complex then this…)...IList<int> result =

(from i in col1join j in col2on i equals j select i).ToList();

told him to re-write it like this…or using a 2 foreach loop, as the join was too complex.IList<int> result = (from i in col1 from j in col2

where i == j select i).ToList();

my Colleague, argued that Microsoft would have implemented the JOIN operator in a better way then a 2 loops running on each other…
I ran a few test on the 2 queries above, and the query that used the JOIN operator was way faster…
The reason is that the JOIN operator (the extension method) is implemented such that the outer collection’s key is enumerated once and put into a hash table, next the inner collection is iterated and it’s key is checked to see if it’s there in the hashtable, this is just O(1) operation, this is way faster then just c…

.Net Reflector to Telerik JustDecompile

I have been using .Net Reflector for almost 4 years now and this really is a cool tool to just go decompile assemblies when you need to, and this was one of the tool I used to decompile some of the assemblies provided by Microsoft to see what's going in the internals.
It was a bit fishy when Reflector was bought by Ants, and gradually as you all might know, Reflector is no longer free, and whats worse the free version will cease to function after May 30th this year.
Enter Telerik, Telerik as promised to release there JustDecompile tool to the public as FREE, this tool gives you almost all the feature .Net Reflector provides. You can download the beta version from here...
Below shows a screen shot of JustDecompile

Entity Framework and POCO - No Support for Xml or Enums

I have been keeping up to some pace on Entity Framework, however did not try a lot on it.So thought of doing a sample on POCO support with Entity Framework.
This was a class I used to insert to my database. public class Task { public long TaskID { get; set; } public XElement TaskParameter{get;set;} public string TaskType { get; set; } public DateTime EnquedTime { get; set; } public DateTime CompletedTime { get; set; } public Guid TaskIdentifier { get; set; } public TaskStatus TaskStatus { get; set; } public string ErrorDescription { get; set; } public TaskPriority TaskPriority { get; set; } }
The property TaskParameter is an XML column in the database and the properties TaskStatus and TaskPriority are enums and are implemented as smallint in the database
Now, I try to instantiate a context and i get this error...
"Mapping and metadata information could not be found for EntityType Task"
To find out the issue…

WCF Configuration Nightmare, MSBuild, IIS AppCmd

In this post I am going discuss about some of the deployment nightmare that you might have when you design SOA, where you segregate logic into several decoupled services. the post would not really deal with production deployment , but about internal developer releases.
The problem here is that when you have multiple services, and you want to deploy your code in one of the test environments for testing before you release it to the testing team, you have a huge amount of configurations that you need to change. This typically includes...
1) Changing service addresses, this might include WCF services that your service has referenced. Sometimes it might be the case that one of this service refer not just one service. All the service might not be deployed in one machine, hence, referring localhost will not work.
2) Changing database connections, this might be a cumbersome task, you might have to go into each and every configuration file and change the database serve , database user or database …

Moving Session Data from InProc to State Server or Database And There Problems

Its been a while since i posted , almost 4 months now, was busy with office work.
So in this post I would like to talk about ASP.NET sessions. we all know about ASP.Net sessions, we all know there are few methods which you can use to store session information, one common way and default way is store session state in the memory of the machine in which ASP.NET is running, the other way is to use the ASP.Net state server or to use the default SQL Server provider to store session data, we are not going back to the basics however, we should be careful in choosing where the session data will be stored and what sort of data will be stored.
It's particularly important to know that moving session data from one mechanism to another (in proc to state server)is not just a matter of changing the configuration file.
When using in-proc data is stored in memory, but when storing it in the state server or on a database like SQ Server, these session data needs to be serialized.

Not all data is …

File Transactions (TFX)

There are situations where a transaction span into a database and to the file system, typically this is handled by running the database call inside a transaction scope and the do the file update call after the database call returns.If the database call fails then nothing is updated into the file system, however if the file update fails then the database transaction is rolled back. The above approach has to be done for the reason that the file update does not participate with the DTC. But what if this we are dealing with multiple files, or any other complex scenario? This is an article one of my friends (Mihidum) forwarded me about NTFS file system transaction, here is the link.
Too bad, .Net does not support this, and we have to write unmanaged code.