At the moment, it is only possible to create the tables, views, stored procedures, synonyms of a database in the Virtual DataPort.
Hence, I would use the "**ROWNUM()**" function in order to generate a number sequence by performing the following steps in Virtual DataPort Administration Tool:
1. Create a selection view on top of the base view by right-clicking the view and navigate to 'New > Selection' option.
1. Click on the 'Output' tab and select 'New field' option to add a new field.
1. Provide a name to the field in the 'field name' parameter and specify the "ROWNUM()" function in the 'field expression' parameter.
1. Then click on 'Save' to save the view.
By executing the view, the "ROWNUM()" function returns unique number for each row. Additionally using "ROWNUM()" function, I can also generate a unique value for each query even if the data were retrieved from different data sources.
For more information, you could have a look at the section [ROWNUM](https://community.denodo.com/docs/html/browse/6.0/vdp/vql/appendix/syntax_of_condition_functions/other_functions#rownum) of Virtual DataPort VQL Guide.
Hope this helps!!