You define GLOP mappings to map specific types of GLOP data, for example role type data or user type data. The system uses the context in which an external routine runs to map the actual data that the external routine can access.
For example, you can define a GLOP mapping for role type data. The actual GLOP data that the system maps for a specific external routine invocation depends on the current role for the user that runs the external routine. If the user does not have a role, or if there is no GLOP data for the current role for the user, the external routine has no access to role type data.
The following diagram illustrates how three different GLOP mappings can potentially map to actual data that you store in the system table.