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I am learning SSIS for a new requirement. I came across these two transformations - Data Conversion and Derived Column. But we can convert the datatypes in Derived Column itself. So what was the need that Microsoft added this 'data Conversion' transformation? I searched in google but did not get the proper answer.

Be1ng_Kr1Sh
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Hope this helps:

The purpose of Data conversion is to do just data conversion.

While Derived column task is used for most of the transformations. To achieve this, data conversion is also put in as a part of it. If you are just intending to do data conversion and no other transform, for simplicity and readability of the package.

Data conversion gives a simple UI to the end user for full filling the requirement of changing the data type of incoming columns.

Derived columns also can help us to achieve data conversion but there we have to explicitly write a code to type cast that.

To give an anology: you can read an Excel file in the dataflow using an Excel source or an OLE DB Source. Doesn't mean the Excel source shouldn't be there. It's easier to use.

Source: Code project

Prabhat G
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  • Also I think the performance of Data Conversion is comparatively better. You can refer this- https://blogs.msdn.microsoft.com/sqlcat/2009/12/01/performance-comparison-between-data-type-conversion-techniques-in-ssis-2008/ Thanks for your response. – Be1ng_Kr1Sh Feb 06 '18 at 09:37