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Looping Through Variable Values with a ForEach Loop Container

  • 16 August 2013
  • Author: ShawnHarrison
  • Number of views: 55959

Have you ever done something in SSIS that you wish you had a need to do more often? That happens to me on occasion. I have a tendency to test out random scenarios when I get bored. You read correctly, I play with SSIS when I am bored. Between my PS3 and SSIS, my Saturday nights are insane!


This is a little tutorial on looping through variable values; one of the little things that will make you feel rather awesome.


The first thing I am going to do is drag an execute SQL task into this empty SSIS package, and pull in some email addresses from table in the AdventureWorks2012 database. Create a connection manager and be sure to set the 'Result Set' property to 'Full Result Set'.



Click 'Result Set' on the left side of the window.



Click the 'Add' button at the bottom of the window. This is how you will assign a variable to contain the results return by a query. It creates a default entry called 'NewResultName'.



Change the result name to 0. In the 'Variable Name' field, select . This opens the 'Add Variable' window. Enter a name for the variable (for example, objEmailAddress). In the 'Value Type' drop down list, select object. Click OK.



Use this as your SQL statement?

   1: Select emailaddress
   2: from person.EmailAddress
   3: where EmailAddressID between 10 and 20


Click OK again to close out the task editor.


Now, I need a variable that will hold each individual email address. Open the variables window and click the new variable icon.



It creates a default variable called 'Variable1'. Click on the name and change it to strToAddress. In the data type drop down list, choose 'String'. Don?t worry about the value for now.



Now, add a ForEach Loop container and connect the execute SQL task to it. Drag in a script task and drop it in the container.



Double click the container to open the editor.  Click 'Collection' on the left side of the window and in the 'Enumerator' drop down list, select 'Foreach ADO Enumerator'. For the 'ADO object source variable' selection, choose the object variable that contains the result set. In my example, it's objEmailAddress.



On the left side of the window, click 'Variable Mappings'. In the 'Variable field', open the drop down list and select the string variable. Mine is called strToAddress. The index is set to 0 by default. Leave that as is. Click OK to close the editor.



Open the script task. The language I am using for this is Visual C#. In the 'ReadOnlyVariables' field, click the ellipses to open the variables list. Select the check box next to the string variable (strToAddress) and click OK.



Toward the bottom of the window, click 'Edit Script'. This is where the fun starts. I will add a script that displays a message box that shows the value of the strToAddress variable. Toward the bottom of the editor, you will see a comment that reads //TODO: Add your code here. This, of course, is where we will add the code. Enter the following code?

   1: MessageBox.Show(Dts.Variables["strToAddress"].Value.ToString());


Close out of the editor. This will compile the script for you and takes you back to the script task editor. Click OK to close it.


Now, execute the package, sit back and watch the magic. The Execute SQL task retrieves all the email addresses and stores them in 'objEmailAddress'. The ForEach loop container reads through the values stored in that variable and rights the first one into 'strToAddress'. The script task displays the current value of 'strToAddress' and then the loop starts again. This continues to the end of the result set.


The script is a way to test to make sure it is working properly. I can replace that with another task such as a send mail task to send emails to each address.




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