http://www.sqlservercentral.com/blogs/salvoz-sql/2012/12/08/ssis-character-replacement-using-the-script-component/

Printed 2014/12/20 02:23PM

SSIS: Character Replacement Using the Script Component

By Jennifer Salvo, 2012/12/08

When cleansing data from source systems to store in a data mart or warehouse, we often need to remove or replace characters.  I recently used the Script Component in SSIS to cleanse some ticket tracking data and thought I’d write a blog post that outlines the implementation.

The data from the ticket tracking system contained characters that needed to be replaced.  Here’s a sample of the data directly from the source system.

We need to replace the __u with a dash and the __b with a space, so the cleansed data looks like this:

The first step is to create an SSIS variable to store a character replacement string, the string stores each unwanted character and the associated replacement character separated by a pipe and contained within curly braces:

{__b| } {__u|-}

Here’s an example from SSIS (with some additional characters included).  The variable name is ‘Replacements’.

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Next, in the SSIS data flow, we need to add a Script Component Task.  The Script Component Task should be configured as follows:

Set the Script Component Type to ‘Transformation’.

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On the Script tab, set ReadOnlyVariables to the user variable that stores the character replacement string (User::Replacements in this example).

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In the ‘Input Columns’ tab, select the column that contains the characters to be replaced.  In this example, the column is called ‘SubmissionMethod’.  The ‘Usage Type’ should be set to ReadWrite.

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After updating the ‘Input Columns’ tab, return to the ‘Script’ tab and click the ‘Edit Script’ button.  (Note: I am using C# in the upcoming sample code)

In the public class ScriptMain : UserComponent, we will add a Dictionary object to store the <Key, Value> pairs representing the original characters and related replacement characters.  In this example, the Dictionary object is called ‘replacements’.

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We then modify the PreExecute method to load the replacements dictionary with the <Key, Value> character pairs stored in the SSIS variable we created earlier named Replacements.

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Next, update the Input0_ProcessInputRow method to load the text from the SubmissionMethod column into a StringBuilder object.  We can then loop through all the characters stored in the replacement dictionary and use the StringBuilder replace method to perform any necessary character replacements.

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The complete code is included below:

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