Selection of Datasource at Runtime

Each Cognos connection to a database is composed of three parts : DataSource -> Connection -> Signon. 

- Each DataSource can have 1..N Connections 

- Each Connection can have 1..N Signons 

You should be able to accomplish your goal by having 1 DataSource with 2 Connections (one connection points at your production DB, the second connection points at your day old copy). 

Then you point your single Package at the 1 DataSource. Each time you run a report associated with this Package, the user will be prompted : "Which connection would you like to use?"