Jon's Blog

.NET Development & More

Using SQL Session State with Multiple Environments

I really like storing Session State out-of-process in a SQL Server database. However, I use custom code that switches the connection string based on the current environment my code is running in (test, stage, production, etc.). It was a little tricky to get this setup properly. But I am pretty happy with the following solution.

  • First, you have to setup the Session State database on the SQL machines/environments you are interested in storing your out-of-process session state in. You need to execute a command similar to the following on the command line to build out the database structure:
    aspnet_regsql -S localhost -E -ssadd -sstype p
    See this link for further information: http://msdn.microsoft.com/en-us/library/ms229862%28v=vs.100%29.aspx
  • Add the following line in your web.config under the <system.web> node. Make note of the partitionResolverType. We will discuss that further in the next step.
    <sessionState mode="SQLServer" partitionResolverType="MyApplication.Utility.SessionConnStringResolver" timeout="60" cookieless="false"/>
  • The partitionResolverType above can reference a cusom class that can be used to choose which connection string you want to use at run-time. For example you can create the following class for dynamically switching your connection string:
namespace MyApplication.Utility
{
    public class SessionConnStringResolver : System.Web.IPartitionResolver
    {
        public void Initialize() { }

        // Return the correct ASP.NET Session DB for the current running environment
        public String ResolvePartition(Object key)
        {
            // Custom code to get connection string based on current environment
            return MyConfigClass.GetConfigSettings.SessionDBConnString;
        }
    }
}

 

If you are using LINQ to SQL you should also set Serialization Mode to Unidirectional on the Object Relational Designer as discussed in this link. This allows you to serialize/deserialize your LINQ classes when saving to the database.

For a better explanation of the Partition Resolver feature of SQL Server Session State see the following links. Above is just the steps I followed to set everything up.

How to Use FreeTextTable

The FreeTextTable function in SQL Server is very useful when you need to search a column for words, phrases, etc. FreeTextTable will return a table that you can join on.  It also returns the Rank of the matches so you can order the most relevant matches at the top.

In the example below I am searching the Keywords column of the MyTable table using the @Keywords passed into the stored procedure.  I am then ordering them by Rank so the highest matches show up first.

CREATE PROCEDURE [dbo].[FreeTextSample]
    @Keywords [varchar](1000) = ''
WITH EXECUTE AS CALLER
AS
BEGIN
    SET NOCOUNT ON;

    SELECT myTable.MyPrimaryKeyID,
        myTable.Title,
        myTable.Description
  FROM MyTable myTable(nolock) INNER JOIN FreeTextTable(dbo.MyTable, Keywords, @Keywords) AS searchTable ON myTable.MyPrimaryKeyID = searchTable.[KEY] ORDER By searchTable.[RANK] DESC END GO

 

One thing to note is that LINQ does not contain an equivalent keyword for FreeTextTable.  So what I did was to create a new method on my DataContext that returns the results of the stored procedure.  See my post here for further details on how to do this.

Source Safe: The character encodings on these files are different. Only files with the same character encoding can be merged or compared.

We saw the above message in SourceSafe after moving to SQL Server 2008 and then saving the scripts for our tables back to SourceSafe.  It appears that SQL 2008 Management Studio uses a different text encoding than prior versions of Management Studio/Enterprise Manager.

To save your script using a specific text encoding.  You can "Save as.." and then there is an arrow to the right of the Save button.  Click this and select "Save with Encoding...".  Then you can select the specific encoding you need.  In my case I needed to change the encoding from "Western Eurpean (Windows) - Codepage 1252" to "Unicode - Codepage 1200".

 

 

SQL Server Trigger for Row Archive

This trigger will write to an archive table when a row is updated or deleted.  Very useful when you want to know who did what and when.

USE [DatabaseName]
GO

SET ANSI_NULLS ON
GO
SET QUOTED_IDENTIFIER ON
GO

CREATE TRIGGER [dbo].[trigTableName_Archive] 
   ON  [dbo].[TableName]
   FOR UPDATE, DELETE
AS 
BEGIN
    SET NOCOUNT ON;
    
    INSERT INTO TableName_ARCHIVE
        (Column1,
        Column2,
        Column3)
    SELECT
        Column1,
        Column2,
        Column3
    FROM deleted

END