What hadoop version are you using with BDM?
Hortonworks supports Hive ACID so you should be able to implement SCD-2 using update strategy transformation. For HDP 2.6 you need to follow below guidelines to enable ACID on hive
1) The user initiating the Hive session must have WRITE permission for the destination partition or table.
2) ZooKeeper and in-memory locks are not compatible with transactions.
3) Only ORC files are supported.
4) Destination tables must be bucketed and not sorted.
5) It only supported isolation level is Snapshot.
For other distros you will need the target hive table to be partitioned and follow approach 2 in the below kb.
Here is link to different Strategies for Incremental Updates on Hive in Big Data Management .