Who is the leader in Operational Database Management System?

This is the definition of Operational Database Management System(ODBMS) according to Gartner (5/10/2016):

"The operational database management system (OPDBMS) market is concerned with relational and nonrelational DBMS (see Note 1) products suitable for a broad range of enterprise-level transactional applications, and DBMS products supporting interactions and observations as alternative types of transactions"

Based on this definition and other considerations Microsoft is the leader edgin higher than the secodn Oracle. This is what you see in the Magic Quadrant. Microsoft shares the vision with others such as Oracle, SAP, AWS and IBM.

Here is copy of the Quadrant:

Detailed report here to download after registering:
https://info.microsoft.com/gartner-odbms-magic-quadrant-register.html?ls=website

Magic Quadrant: Microsoft is tops in Operational Database Management Systems

Operational Database Management System (ODBMS) which is a more appropriate name than OLTP there has many new entrants to the business. It is not just RDBMS anymore as you have Big Data, NoSQL, etc.

Microsoft is tops in Gartner's Magic Quadrant for Operational Database Management Systems for 2015. Oracle is a little behind Microsoft and IBM is trailing.

Here is the picture of the Quadrant: