With Oracle losing ground to SQL Server, and probably alot more in the next few years with Oracles featureless (non-option) 12c I think it pays to know about the enemy as many DBA jobs now require bi platform knowledge . Microsoft have been nice enough to put together free training videos for Oracle DBAs
Become A Bilingual DBA*
an Oracle DBA (possibly certified) who masters Microsoft SQL Server knowledge (possibly certified)
http://www.microsoft.com/en-us/sqlserver/learning-center/bilingual-dba.aspx
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