APEX

ahoj!

is it possible to use a substitution string in a select-statement as db-link? if yes, how? for example:
application definition -> substitution string: DB_WORK, substitution value: pwork_pwork
how can i use the substitution string DB_WORK in a select-statement?

select * from test@DB_WORK should result in select * from test@pwork_pwork, but this doesn't work. v('DB_WORK'), &DB_WORK. and :DB_WORK is also not possible. (error message: Query cannot be parsed within the Builder...)

background: i have a test- and production-application. in the test-app i use pwork_pwork as db-link, the production-app should use work_work. the apex-database is for both environments the same.

thx!

bye,
christian