In Integration Services, a variables collection is available on all containers: packages, looping structures such as the Foreach container, and the TaskHost container that encapsulates each task. When a package is migrated, the global variables and the variables from SQL Server 2000 DTS tasks are all migrated to the variables collection of the package. For example, the variables used by a SQL Server 2000 Execute SQL task are added to the variables collection of the migrated package.
Integration Services uses namespaces to organize variables. All DTS variables are migrated to the User namespace.
After the package is migrated, you can add functionality to variables in the following ways:
Create additional namespaces and organize variables by namespace.
Use expressions to set variable values.
Specify whether updating the variable value raises an event.