Provides useful information about the publication(s) being synchronized. This script may also be used to manage generation numbers for file-based downloads.

Parameters

In the following table, the description provides the SQL data type. If you are writing your script in Java or .NET, you should use the appropriate corresponding data type. See SQL-Java data types and SQL-.NET data types.

Default action

The default generation number is 1. If no script is defined for this event, the generation number sent to the remote is always 1.

Remarks

This event lets you design synchronization logic based on the publications currently being synchronized. This event is invoked in the same transaction as the begin_synchronization event, and is invoked after the begin_synchronization event. It is invoked once per publication being synchronized.

One potential use for this event is to affect what is downloaded based on the publication used. For example, consider a table that is part of both a priority publication (PriorityPub) and a publication for all tables (AllTablesPub). A script for the begin_publication event could store the publication names in a Java class or a SQL variable or package. Download scripts could then behave differently based on whether the publication being synchronized is PriorityPub or AllTablesPub.

If an UltraLite remote is synchronizing with UL_SYNC_ALL, this event is invoked once with the name 'unknown'.

Generation number

The generation_number parameter is specifically for file-based downloads. The output value of the generation number is passed from the begin_synchronization script to the end_synchronization script. The meaning of the generation_number depends on whether the current synchronization is being used to create a download file, or whether the current synchronization has an upload.

In file-based downloads, generation numbers are used to force an upload before the download. The number is stored in the download file. During a synchronization that has an upload, one generation number is output for every subscription to a publication. They are sent to the remote database in the upload acknowledgement, and stored in SYSSYNC.generation_number.

See also

• Script parameters
• Adding and deleting scripts
• end_publication connection event
• MobiLink file-based download
• MobiLink generation numbers
• Using remote IDs and MobiLink user names in scripts
• Using last download times in scripts

SQL example

You may want to record the information for each publication being synchronized. The following example calls ml_add_connection_script to assign the event to a stored procedure called RecordPubSync.

CALL ml_add_connection_script(
 'version1',
 'begin_publication',
 '{CALL RecordPubSync( 
    {ml s.generation_number}, 
    {ml s.username}, 
    {ml s.publication_name}, 
    {ml s.last_publication_upload}, 
    {ml s.last_publication_download}, 
    {ml s.subscription_id} )}' );

Java example

The following call to a MobiLink system procedure registers a Java method called beginPublication as the script for the begin_publication connection event when synchronizing the script version ver1.

CALL ml_add_java_connection_script( 
 'ver1',
 'begin_publication',
 'ExamplePackage.ExampleClass.beginPublication' )

The following is the sample Java method beginPublication. It saves the name of each publication for later use.

public String beginPublication(
  ianywhere.ml.script.InOutInteger generation_number,
  String user,
  String pub_name,
  Timestamp last_publication_upload,
  Timestamp last_download ) {  
  _publicationNames[ _numPublications++ ] = pub_name;
  return ( null );
}

.NET example

The following call to a MobiLink system procedure registers a .NET method called BeginPub as the script for the begin_publication connection event when synchronizing the script version ver1.

CALL ml_add_dnet_connection_script( 
 'ver1',
 'begin_publication',
 'TestScripts.Test.BeginPub'
)

The following is the sample .NET method BeginPub. It saves the name of each publication for later use.

public string BeginPub(
  ref int generation_number,
  string user,
  string pub_name,
  DateTime last_publication_upload,
  DateTime last_download ) {
  _publicationNames[ _numPublications++ ] = pub_name;
  return ( null );
}