Integration Services (SSIS) is a powerful tool in SQL Server that allows us to create ETL (Extract, Transform, Load) solutions. However, there may be situations where the built-in control flow items are not sufficient to implement certain actions. In such cases, we can use the Script Task to access pre-built .NET assemblies and COM components.
Let’s consider a scenario where we need to access an encrypted file in our ETL solution. We can use an existing .NET assembly for the decryption process and integrate it with SSIS using the Script Task. Here’s how you can do it:
- Drag and drop a Script Task onto your Control Flow.
- Open the Script Task Editor by right-clicking on the task and selecting “Edit” from the context menu.
- Select “Script” in the left pane and click on “Design Script” to open the Visual Studio for Applications (VSA) environment.
- Pass the encrypted file name via the ReadOnlyVariables property.
- Referencing the .NET assembly is done through the Project Explorer. If the assembly is not visible, you may need to manually add it to the appropriate folder.
- Once the assembly is added, you can use it to write code for the decryption process.
After completing the code, you can execute the package to test the encryption routine. If you encounter an error stating “Could not load file or assembly ‘YourAssemblyName’, Version=1.0.0.0, Culture…”, it means that the assembly needs to be added to the Global Assembly Cache (GAC) for access by the SSIS runtime environment. Make sure the assembly is signed before adding it to the GAC.
During the execution of the Script Task, you may encounter runtime errors. By default, SSIS displays a Runtime Error dialog box when an error occurs. However, this dialog box does not appear when running the package with the DTExec utility. To handle errors and display custom error messages, you can use Try/Catch blocks within the Script Task. You can show the error message with a dialog box or write it to the log. If you have implemented any Event Handlers, make sure to raise the FireError event and set the TaskResult to Failure if necessary.
If you are working on a 64-bit environment, you may face challenges when referencing 64-bit assemblies with the 32-bit VSA used by SSIS. In such cases, you need to have a 32-bit assembly with the same name, version, and metadata as the 64-bit assembly. You can reference the 32-bit assembly at design time, and during runtime, the SSIS runtime environment will pick the appropriate assembly from the GAC if it is available.
In conclusion, accessing .NET assemblies in SQL Server Integration Services can greatly enhance the capabilities of your ETL solutions. By leveraging the Script Task and pre-built assemblies, you can implement custom actions and handle complex scenarios efficiently. Remember to handle errors gracefully and consider the compatibility of assemblies in different environments.
We hope this information on accessing .NET assemblies in SSIS has been helpful for your development. If you have any comments or questions, please feel free to share them with us.