Built-in UltraLite synchronization features

UltraLite contains MobiLink synchronization technology in the data management layer for UltraLite. Unlike SQL Anywhere remote databases, you do not need to increase the size of the UltraLite footprint to include synchronization functionality.

Important synchronization features built into the UltraLite runtime include a row-state tracking mechanism and a synchronization state tracking mechanism.

Synchronizing an UltraLite database requires your application to set synchronization parameters identifying the address of the MobiLink server and other required information, and calling a synchronization function or executing the SYNCHRONIZE SQL statement. The option you chose depends on the API you are using.

The row-state tracking mechanism

Synchronization state tracking

UltraLite uses a progress counter to ensure robust synchronization. Each upload is given a unique number to identify it. This allows UltraLite to determine whether an upload was successful when a communication error occurs.

When you first create a new database, UltraLite always sets the synchronization progress counter to zero. A progress counter value of zero identifies the database as a new UltraLite database, which tells the MobiLink server to reset its state information for this client.

Caution

Because UltraLite increments the progress counter each time a synchronization occurs, you cannot synchronize an UltraLite database to different consolidated databases. If the progress counter value is not zero and does not match that sequence number stored in the consolidated database, MobiLink synchronization reports an offset mismatch and synchronization fails. You cannot replace an UltraLite database with a backup copy if the progress counter is older than the current value.

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