PeopleSoft is supported on various 64-bit platforms but PeopleSoft development tools (eg. App Designer, Datamover) are still 32-bit. Currently, if your PeopleSoft application is installed using Oracle 64-bit database and you’re using Oracle 64-bit client to connect to database, you won’t be able to log into PeopleSoft Application Designer or Data Mover.
Note: Application Server and Web Server are already supported on 64-bit and will work fine with Oracle 64-bit Client.
In PeopleTools 8.54 application, Oracle is going to make Development Client as a 64 bit application too and you would no longer need to install 32 bit Oracle client version specifically for PeopleTools connections.
This plan was mentioned in the Oracle Open World 2013 during session that covered Proposed PeopleTools 8.54 Enhancements.