The reason there is a SAP Connector is because SAP will not let you access the database directly. It will cause an infringement of the support agreement.
Other ERPs such as JDE, Oracle Financials, Peoplesoft, etc. do not impose such restrictions on their clients so you can access the database directly thought the standard OLEDB/ODBC connector.
If you don't have enough knowledge about the JDE/Financials data models I would suggest getting some help from JDE/Financials consultants.