In Oracle Streams one way replication from one DB to another is a basic block for many replication topologies (N-way, hierarchical, combined and so on), and changes could be captured and applied for the same table at the same time.
But I can't find anywhere in SQL Server documentation whether table (article) could be a source (publisher) and destination (subscriber) simultaneously. Is it possible, for example, to setup bidirectional replication using two pairs of publisher->subscriber transactional replication?
Naturally I am more interested in multi-level hierarchy: for example one table is replicated from root node through intermediate nodes to leaves, second one – from leaves to root, and third one – bidirectionally, and for all tables intermediate nodes could perform DMLs to be replicated too. With Oracle Streams it is easy to achieve, and even more sophisticated configurations are possible, but are they with SQL Server?
UPDATE: It seems it is with use of merge replication and republishing (http://msdn.microsoft.com/en-us/library/ms152553.aspx), but what about transactional replication?
Best Answer
UPDATE: It seems it is with use of merge replication and republishing, what about transactional replication?
The near to same functionality can be achieved using Peer-to-Peer Transactional Replication. This is the only SQL Server replication technology that allows simultaneous writes at multiple nodes.
Peer-to-peer replication is a logical extension to bi-directional transactional replication handling the data layer only. The replication engine is used to replicate like it says "from everyone - to - everyone".
More info can be found at Publication Types for Transactional Replication. Here is a good example of configuring it.
Refer this white paper for a comparison of SQL Server and Oracle features.