Despite all this, Mr. Ellison does not seem ready to leave Oracle. The executive, who turned 70 last month, said during a conference call with financial analysts that he would “continue doing what I’ve been doing for the past several years,” including overseeing Oracle’s technology development, making final decisions on corporate matters and even appearing on quarterly earnings calls.

The two executives who are replacing him, Mr. Ellison said, “deserved the recognition.”

Oracle’s software and hardware are involved with the ways that companies and large organizations store and manage their data, as well as sophisticated applications for running things like international manufacturing and corporate financial systems.

It is unusual for big technology companies to split responsibilities at the top, but so far the two co-presidents have split much of running Oracle, a company with over 120,000 employees that is based in Redwood Shores, Calif. Mr. Hurd runs service and sales, while Ms. Catz oversees operations and finance.

Still, neither has Mr. Ellison’s technological expertise, nor is either likely to cast anything like the shadow that Mr. Ellison has over his 37-year career.

Born to an unwed mother in New York, Mr. Ellison was adopted by his aunt and uncle and grew up in a Jewish household in Chicago. He is known for a fascination with Japanese samurai culture.

He attended college but did not graduate, and he took a job in the computer business. An early project involved writing for the Central Intelligence Agency a database that could turn numbers into information. The idea, pioneered by IBM, was to relate one set of data to another, for example, a row of people’s names with a column of their birth dates. This, in turn, could be combined in a table of, say, all people born under the astrological sign Leo.

In 1977, working with Robert Miner and Edward Oates, Mr. Ellison created a company called Software Development Laboratories to sell their product, the relational database, to the government. Finishing the project ahead of schedule, they turned their database into software for businesses. After a second name change, the company became Oracle in 1982.