When you created your Database to HL7 channel in Step 2, you exported the tables required by your source (From Database) component. This table was the table you specified in the VMD file in Step 1, called the PatientRegistration table.

The From Database Iguana source component works by polling a status table table for each message in its VMD file. It checks the status table to see if there is any new information to be sent; if there is, it uses the information in the VMD file to send out the new data as an HL7 message. This process is illustrated in the graphic below:

From Database Component