Figure 4

Quadratus, an interface to illustrate S3QL's permission control mechanism and its effect on S3QL queries. Projects, Collections, Rules, Items and Statements associated with GI Clinical Trials Project are displayed with effective and assigned permissions. Collections and Rules retrieved using S3QL queries select( C |P1196457) and select( R | P1196457) inherit the permission assignment in the Project "ysn"; assigned permission "N--" in Collection "Demographics" results in the effective permission of "Nsn" inherited by all Rules and Items that have a relationship with that Collection, effectively preventing gi_user1 from accessing its data. The directed labelled graph of the propagation resolution is displayed on the right side of the application illustrating the propagation mechanism.