If Chinese philosopher Sun Tzu were transported from 500 B.C. to 2004 A.D., he would probably be a high-paid management guru for the software industry. On his lecture circuit, he would quote such strategies from his best-selling book, The Art of Execution: "Software is a matter of life and death. First, you need to attack your competitor with a sudden all-cash hostile takeover. If this is rebuked, then create disorder by dragging your competitor into the American court system."

This is basically Oracle's (NASDAQ:ORCL) business strategy, and it is working perfectly, as evidenced today by PeopleSoft's (NASDAQ:PSFT) warning for its second-quarter sales and earnings. According to PeopleSoft's management, Oracle's hostile bid and antitrust lawsuit is generating bad PR for the firm, which has had "substantial" adverse impact on the company's business.

While Wall Street consensus was for $0.21 a share on $689.3 million in revenues, PeopleSoft indicated that earnings will range between $0.13 and $0.15, with revenues from $655 million to $665 million.

Antitrust trials are costly and time-consuming. Take Lawson (NASDAQ:LWSN), which is an enterprise software company and on the target list for Oracle CEO Larry Ellison. Last quarter, management said that the firm experienced customer pushback because of the trial.

Oracle, on the other hand, does not have to worry about such things. Rather, it has billions of cash on its balance sheet earning a measly amount of interest. Why not use the hoard to blitzkrieg the competition?

True, Ellison has always been a meat eater in terms of dealing with his competitors. But, his hostile takeover attempt and massive fight in the courtroom are signs that the enterprise software market is changing fundamentally. That is, it's not a growth story any more.

So far this week, there have been a variety of major warnings from software companies, such as Veritas (NASDAQ:VRTS) and JDA Software (NASDAQ:JDAS).

Yesterday, we also got the 4,900-word missive from Microsoft (NASDAQ:MSFT) CEO Steve Ballmer, who announced $1 billion in cost cuts and rallied the troops to win more business. Ballmer also warned against new disruptive technologies, such as Linux. Yes, enterprise software developers worry about customer resistance and upstarts such as Salesforce.com (NYSE:CRM) and RedHat (NASDAQ:RHAT).

Many pundits were puzzled when Ellison decided to fight the antitrust suit against the U.S. government. Wouldn't he lose? Of course not. PeopleSoft is the loser.

Sun Tzu would be proud.

Fool contributor Tom Taulli is the author of The EDGAR Online Guide to Decoding Financial Statements. He does not own shares in any of the stocks mentioned.