Licensing
Oracle Corporation makes versions 2.0 and higher of Berkeley DB available under a dual license. This license is a 2-clause BSD license with an additional copyleft clause similar to the GNU GPL version 2's Section 3, requiring source code of an application using Berkeley DB to be made available for a nominal fee.
Thus, the license depends on how a particular application that uses Berkeley DB is distributed to the public. Software that is not distributed can use the Sleepycat License, as can free and open source software. Proprietary software can use Berkeley DB only under a commercial license agreement between Oracle and the application's publisher.
As of July 2011, Oracle's list price for commercial Berkeley DB licenses varies between 900 and 13,800 USD per processor.
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