I did B.tech CSE at 2013 i like to do courses like SAP/Oracle DBA/testing among these can you suggest to be the best course for me?

I think SAP/ ORACLE is the best one

SAP is booming well now in market, so wiith your present qualification itself you can join as Consultant entry level in any SAP oriented consultant firm, After completing one project your experience will take your to GOOD Salary scale and positions 

I can advice you for Oracle ERP courses:

you can start with :

1- R12.x Oracle Applications User Management Fundamentals

2- R12.x Oracle E-Business Suite Essentials for Implementers

then you have to define you way, either to go for technical (development/admin) under Oracle E-Bus. or to go as a functional consultant for Finance, Supply Chain, HCM, CRM, EAM,etc;

If you choose the technical (development/admin), then you have to take:

1- R12.x Oracle Applications System Administrator Fundamentals

2- R12.x Oracle Applications Framework QAF;

3- Oracle ADF, Oracle Workflow, Oracle Alerts, Oracle AME, etc

if you choose functionla then specific course for each has to be attended.

I hope my answer benifits you;