SAP, the German business software giant, has announced a $4.3 billion takeover of Ariba to expand its cloud computer services. Ariba shareholders will be offered $45 per share, meaning a premium of almost 20%.

This indicates that SAP’s battle with other tech giants like Oracle continues. This year, SAP has already made 2 deals. And later last year, SAP took over SuccessFactors for $3.4 billion. Oracle agreed to buy Taleo, which is SuccessFactors’ rival, in February, and agreed to buy Rightnow Technologies last year.

Ariba is the second largest cloud vendor by revenue. The acquisition is expected to close in the 3^rd quarter of 2012.