Close on the heels of the former Hewlett-Packard (HP) CEO Mark Hurd’s Monday appointment as a co-president at rival database software maker, Oracle Corp., HP Tuesday filed a lawsuit in a California state court to prevent Hurd from joining Oracle.

With Hurd being chiefly responsible for leading Oracle’s efforts to lure businesses away from HP, the lawsuit claims that Hurd’s official responsibilities at Oracle may require him to reveal HP’s trade secrets; and thus violate a confidentiality agreement that he had signed as part of a nearly $40-million severance package from HP after his last-month ouster from the company.

The lawsuit filed by HP largely highlights the growing bitterness between HP and Oracle – the two companies which, for nearly 25 years, have worked in tandem to ensure that their respective products work well together.

However, ever since Oracle’s $7.4 billion acquisition of Sun Microsystems – a deal that allows Oracle to sell computer servers for powering the back office operations of companies –, the relationship between HP and Oracle has started straining. 

Noting that the HP lawsuit may deliver the final blow to the HP-Oracle association, Oracle’s CEO Larry Ellison said in a Tuesday statement: “The HP board is acting with utter disregard for that partnership, our joint customers, and their own shareholders and employees. The HP Board is making it virtually impossible for Oracle and HP to continue to cooperate and work together in the IT marketplace.”