How to set a variable as an Alias for a Datastore

Hi everybody,

I would like to know if it's possible to set a variable as an Alias for a Datastore, and how to do it, so that when I execute a Job, I can choose the database schema at that moment through the Global variable tab.

My idea would be then:

1º) Create for my job a Global Variable called '$Schema' and establish 'DEV' as its default value

2º) Create an alias in my datastore "DATA" like "DATA = $Schema"

Then, when I press "Execute" over the Job that uses the datastore "DATA", I will be able to use either the default schema ('DEV') or change it to another one ('PRE', 'PRO', etc).

In conclusion, what I'm looking for is the possibility of choosing the environment at execution time, but when I try to do what I've explained above, the job gives me an error:

error message for operation <create table>: <ORA-20002: ORA-01918: user $SCHEMA does not exist

Thanks in advance and best regards