(Reuters) - Oracle Corp has ended a high-profile computer-building partnership with Hewlett-Packard Co as Oracle prepares to acquire Sun Microsystems Inc, a rival of HP.

Sun, the world's No. 4 server maker, and Oracle have jointly developed a second-generation version of a specialized database computer, dubbed Exadata. Oracle and HP launched the first version a year ago.

Oracle Chief Executive Larry Ellison unveiled the new machine on Tuesday, almost a year after he announced his company's entry into the hardware business with help from HP. At the time, he said that HP would be a key ally in that effort.

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But the dynamics of that relationship have changed since April, when Oracle agreed to buy Sun for more than $7 billion. Hewlett-Packard and Sun are fierce rivals in the markets for server computers and storage equipment.

The new Exadata computer is the first of what Ellison has said will be many products that wed Sun's hardware with Oracle's software.

An Oracle spokeswoman said Oracle would continue to sell the Exadata computers, built in partnership with HP, until existing inventory is sold out, if customers request that model.

Officials at Hewlett-Packard could not be reached for comment.

When Ellison unveiled the HP partnership a year ago, he told customers that the product could not have been developed without that company's assistance.

On Tuesday he bragged that Sun's technology made the database computer far superior to hardware from rivals including Teradata Corp and Netezza Corp.

"Everything is bigger about Exadata, Version 2. Everything is faster about Exadata, Version 2," he said during a presentation to customers that was broadcast over the Internet.

Oracle does not break out sales of the Exadata machine. But during the company's most recent earnings call, Ellison said that it was one of the most successful products he had launched since he founded the company more than 30 years ago.

(Reporting by Jim Finkle, editing by Matthew Lewis)