Synchronization from the source database to the mobile device

Obrázek 6 shows how changes from a source table are applied to a DB2 Everyplace table on the user's mobilní zařízení during synchronization. The Sync Server sends to the user all relevant source data changes that have been made since the user's last synchronization. The Sync Server sends only changed data that the user is subscribed to.

The numbers in the figure correspond to the explanations following it.

Obrázek 6. How changes to the source database are applied to the mobile database

Begin Figure 3. Four boxes, the first box representing a source system, the second box representing a mid-tier system, the third box representing a synchronization reply, and the fourth box representing a mobile device. The box representing a source system contains a VNMEDICALRECORD source table. The VNMEDICALRECORD source table has an arrow pointing to the DB2 log. The DB2 log has an arrow that points to the capture program. The capture program has an arrow that points to change data table. Change data table has an arrow that points to apply. Apply has an arrow that points to the VNMEDICALRECORD mirror table in the mid-tier system. The VNMEDICALRECORD mirror table has an arrow that points to the output queue. The output queue has an arrow that points to the synchronization reply box. The synchronization reply box has an arrow that points to the VNMEDICALRECORD (DB2 Everyplace table) in the mobile device box. End Figure 3.

  1. The DB2 DataPropagator Capture program, running continuously on the source system, captures changes to the VNMEDICALRECORD source table from the DB2 log and writes them to the CD table.
  2. The DB2 DataPropagator Apply program applies changes from the CD table to the mirror table, VNMEDICALRECORD. If update conflicts are identified they are resolved during this step of the process.
  3. The changes to data are sent to an output queue on the mid-tier system as a synchronization reply message.
  4. The synchronization client software retrieves the synchronization reply message from the output queue. The client retrieval request is authenticated.
  5. The changes to data are applied to the client's local copy of the table. The synchronization session ends.

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