Export data from SQL Server on update - sql

Question

I need to export data from SQL Server when a specific column is updated and wonder if there is some recommended way to do this?
I have a table with an column 'Activated', when this value is changed to true an export should be trigged.
I soppose I need a trigger that reacts on changes in the 'Activated'. And my two options at present is to call the webservice directly from the trigger or let the trigger insert data in a table that my one service reads from and calls the extern service.
Is any of this ideas preferable or is there any other better solution?

Answer 1

you should check out the SQL Server Service Broker - it can be used to trigger external actions on changes to the data.
one implementation (which I have not used) can be found here: http://lab.arc90.com/2009/02/05/sqlwatcher-ad-hoc-database-change-monitoring/

Answer 2

If you have infrequent changes in data (for example classified values), you can use Query Notifications + SQLDependencies class. Behaind the scene its also uses Service Broker #paul mentioned.
For example, you can have table:
CREATE TABLE dbo.MyTable
(
MyTableID INT not null PRIMARY KEY IDENTITY,
SomeText nvarchar(50)
)
And SQL code (user rights are discussed here):
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Data.SqlClient;
namespace TestApp
{
class Program
{
static void Main(string[] args)
{
SqlDependency.Start("server=<MyServer>;database=<MyDB>;User ID=<user>;Password=<pwd>;Integrated Security=false;");
Console.WriteLine("Started..");
get_msg();
Console.ReadLine();
SqlDependency.Stop("server=<MyServer>;database=<MyDB>;User ID=<user>;Password=<pwd>;Integrated Security=false;");
}
private static void get_msg()
{
using (SqlConnection con =
new SqlConnection("server=<MyServer>;database=<MyDB>;User ID=<user>;Password=<pwd>;Integrated Security=false;"))
{
SqlCommand com = new SqlCommand("SELECT MyTableID, SomeText FROM dbo.MyTable ", con);
SqlDependency dependency = new SqlDependency(com);
dependency.OnChange += new OnChangeEventHandler(dependency_OnChange);
con.Open();
com.ExecuteNonQuery();
}
}
static void dependency_OnChange(object sender, SqlNotificationEventArgs e)
{
Console.WriteLine("dependency Info = {0}, time: {1}",e.Info, DateTime.Now);
get_msg();
}
}
}