Oracle stream and standby database

Question

i want to implement stream(table level) in the following scenario
what i must to set for standby as when i switch to standby database the stream work correctly like when primary was working.
DB1--------------------stream---------------------DB2
DB1standby .......................................DB2standby
Narges.

Answer 1

Your schema above do not tell us if this is a streams master/master. Also it is important to know if you a doing full schema replication or only some tables.
For the db_name think global name : how do you setup a propagation when the source DB and target DB have the same TNS entry - whose name is driven by the rule dblink name = global_name = tns entry.
Here it is a slightly different case : DG will succeed to SRC and appear as the same DB for the remote though they are on different hostname. Only way is the fail over in tns entry when you set multiple host for the same services.
The rest should be ok except for the lost data of SRC which requires a re-sync.
On the streams side problems remains and I am still skeptic on the feasibility : on paper no problems but problems come fast for the data's lost during the switch to DG (and this is to be expected with async DG, last SCN's will be missing on DG but not necessary on remote target site).
Then both sites will start suffering on the loss of this data most probably with ORA 1403 data not found or Streams transactions pending and there is no way to predict the extend of this in advance. The re-sync of this status is then crucial and I am working on this. I will come back to the community with a generic procedure for master-master re-sync. One of the main problem is to identify table remote correspondents: These are easy to determine for declarative transformations but for transformation done within apply handler or transformation function associated to a context I have not find better than to comes back to the DBA and ask pitifully which are the remote target tables. The correspondence is a precious data that do not appear in any data dictionary view, but is only into the text of a pl/sql block.
For my comments on the others thread, when the former SRC comes back, I have not considered the possibility in 11g to re-sync the former Master with a DG being the new master and sound like I should have.
But this is all new also for me and I need to test it. if it works then you don't have the problem to setup a downstream capture between 2 DB having the same db_name.