Defining Portal Systems and Aliases 
In the portal, be sure that you have created each system required for application modeling, and assigned it a system alias accordingly.
For information about creating systems and aliases, see the Portal Administration Guide on SAP Help Portal at help.sap.com/nw70
Map users with VC Role to a user with read permissions to the required back-end system.
The Visual Composer installation includes the Business Intelligence (BI) extension kit for accessing and building queries against a wide range of data sources created with the BI Java Connectors and SAP BI Connector. These include SAP BI systems as well as non-SAP data sources. The BI functionality available in Visual Composer differs depending on which type of connector you use to define your system:
Systems created with a BI Java Connector can access the BI Integration Wizard and the SQL or MDX Editors, or can be used as data services with a default relational or OLAP query.
Systems created with the SAP BI Connector provide access to SAP BI queries, query views, and characteristics in Visual Composer. For more information on configuring a connection to an SAP BI system, see the following path in the SAP Customizing Implementation Guide: .
See Appendix: Visual Composer Connectivity for details on the full range of systems you can create for use in Visual Composer.