Can I use Aspose.BarCode to create a barcode image programmatically at the back end?

Yes, with the help of Aspose.BarCode you can programmatically create images of barcode at the back end. For more information, please have a look at: Using with Console Applications

Is there any way to save a barcode image to a Memory Stream, without first storing it to the hard drive, so that it can be saved in SQL Server database as an image field ?

Yes, it is possible. For more information, please have a look at: Save Barcode Image to Streams

How can I set the license for Aspose.BarCode in my applications?

There are many different ways in which you can set the license for Aspose.BarCode. To get detailed information about these, please have a look at: Licensing