One of the ways of erasing a project from the Decision Center database is to use an Ant task.
To erase a project, including all its content, run the drop-project Ant task with the following parameters:
-Dserver.url=<server url>
-DdatasourceName=<data source name>
-DprojectName=<project name>
You cannot drop a project if another project depends on it.
You can also erase projects directly from Decision Center, as described in Erasing the current project.