A standalone project management tool might not be able to cater to all relevant functions like finance, operations, PMO, logistics etc. And even if it; it would be asking for lot of duplicate entries that would be there as origin level entries at various points in various other applications. These other applications might be the legacy applications in use because of the unique functionality they are catering to, or the newly implemented main/ core business application covering most of the business functions.
Whatsoever is the case, entry of same kind of information in two or three places again not only takes away lot of efforts and time but also invite errors while entering the same data at various places. That is the purpose that if the data is available in any other applications – be it legacy or core business application like ERP, it is important to integrate it with your project management tool by building an interface or web services for the purpose of pushing or pulling; writing to or writing back; all identified important pieces of information. If need be, and if specified by security norms in the organization, for interfaces, encryption and decryption can be deployed depending on the severity of information flowing from one database to another.