Oracle has filed a legal complaint against arch-rival SAP and its TomorrowNow subsidiary, alleging that the German software maker engaged in corporate espionage. 

Oracle said in its legal complaint that SAP had engaged in "corporate theft on a grand scale" including the theft of "thousands of proprietary, copyrighted software products and other confidential materials that Oracle developed to support its customers".

TomorrowNow is a consultancy firm that SAP acquired in 2005. The company specialises in supporting PeopleSoft and JD Edwards software, both of which are Oracle subsidiaries. 

Following its acquisition by SAP, TomorrowNow has focused on migrating users to SAP software.

Oracle claims that the 'stolen' information aids SAP's migration efforts, a process that is typically time consuming and expensive.

SAP allegedly started using customer log-in credentials in November to gain access to Oracle's Customer Connection website and download the data, according to Oracle.

SAP is accused of using accounts for Oracle customers that were about to migrate, such as Honeywell, as well as customers who had cancelled their Oracle subscriptions in favour of SAP's software such as Metro Machine Corp.

In one case, it was alleged, an account was used to download 1,800 items a day for a period of four days. The average Oracle customer downloads 20 items per months.

Oracle's customer support materials are protected by copyright law. Access is granted only to customers with current support contracts for the software.

Oracle is demanding unspecified damages as well as a court order that bars SAP from future infractions and forces it to return the 'stolen' materials.

A spokesperson for SAP said that the company is studying the allegations and could not comment.

Oracle and SAP are engaged in a fierce battle over market share in the enterprise software market.

Both firms have so-called defector programmes that offer rebates and freebies for customers to switch, and their executives occasionally take on their rivals in verbal mud-slinging contests.