Resource components are used to provide access to data that resides outside of MD Link. For example a Database Resource component can be configured to extract data from a SQL database.
Each resource component has an output schema that appears in the Source tree of the Data Mapping tab of each of its downstream task components. This allows you to map the resource component’s data (in this case, database data) to the task’s input schema.
Resource components do not have an input schema – they are output-only components.