At the connection level, the sequence of major events is as follows:
begin_connection begin_synchronization begin_upload end_upload prepare_for_download begin_download end_download end_synchronization end_connection
When a synchronization request occurs, the begin_connection event is fired. When all synchronization requests for the current script version have been completed, the end_connection event is fired. Typically you place initialization and cleanup code in the scripts for these events, such as variable declaration and database cleanup.
Apart from begin_connection and end_connection, all of these events take the MobiLink user name stored in the ml_user table in the consolidated database as a parameter. You can use parameters in your scripts by placing question marks where the parameter value should be substituted.
To make scripts in SQL Anywhere databases easier to read, you might declare a variable in the begin_connection script, then set it to the value of ml_username in the begin_synchronization script.
For example, in begin_connection:
CREATE VARIABLE @sync_user VARCHAR(128);
In begin_synchronization:
SET @sync_user = ?
The begin_synchronization and end_synchronization events are fired before and after changes are applied to the remote and consolidated databases.
The begin_upload event marks the beginning of the upload transaction. Applicable inserts and updates to the consolidated database are performed for all remote tables, then rows are deleted as applicable for all remote tables. After end_upload, upload changes are committed.
If you do not want to delete rows from the consolidated database, do not write scripts for the upload_delete event, or use the STOP SYNCHRONIZATION DELETE statement in your PowerScript code. For more information, see “Deleting rows from the remote database only”.
The begin_download event marks the beginning of the download transaction. Applicable deletes are performed for all remote tables, and then rows are added as applicable for all remote tables in the download_cursor. After end_download, download changes are committed. These events have the date of the last download as a parameter.
Other connection-level events can also occur, such as handle_error, report_error, and synchronization_statistics. For a complete list of events and examples of their use, see the chapter on synchronization events in the MobiLink Administration Guide.
