Immediately before a hook is called, dbmlsync creates the #hook_dict table in the remote database, using the following CREATE statement. The # before the table name means that the table is temporary.

CREATE TABLE #hook_dict(
name VARCHAR(128) NOT NULL UNIQUE,
value VARCHAR(10240) NOT NULL)

The dbmlsync utility uses the #hook_dict table to pass values to hook functions, and hook functions use the #hook_dict table to pass values back to dbmlsync.

Each hook receives parameter values. Sometimes, you can modify the value to return a new value; others are read-only. Each row in the table contains the value for one parameter.

For example, suppose two subscriptions are defined as follows:

CREATE SYNCHRONIZATION SUBSCRIPTION sub1
TO pub1
FOR  MyUser;
SCRIPT VERSION 'v1'

CREATE SYNCHRONIZATION SUBSCRIPTION sub2
TO pub2
FOR  MyUser;
SCRIPT VERSION 'v1'

When the sp_hook_dbmlsync_begin hook is called for the following dbmlsync command line

dbmlsync -c 'dsn=MyDsn' -s sub1,sub2

the #hook_dict table contains the following rows:

A hook can retrieve values from the #hook_dict table and use them to customize behavior. For example, to retrieve the MobiLink user you would use a SELECT statement like this:

SELECT value
FROM #hook_dict
WHERE name = 'MobiLink user'

In/out parameters can be updated by your hook to modify the behavior of dbmlsync. For example, in the sp_hook_dbmlsync_abort hook you could instruct dbmlsync to abort synchronization by updating the abort synchronization row of the table using a statement like this:

UPDATE #hook_dict
SET value='true'
WHERE name='abort synchronization'

The description of each hook lists the rows in the #hook_dict table.

 Examples

CREATE PROCEDURE sp_hook_dbmlsync_delay()
BEGIN
   DECLARE delay_val integer;
 SET delay_val=DATEDIFF(
   second, CURRENT TIME, '19:00');
 IF (delay_val>0 AND
     delay_val<3600)
 THEN
 UPDATE #hook_dict SET value=delay_val
   WHERE name='delay duration';
 END IF;
END

CREATE PROCEDURE sp_hook_dbmlsync_begin()
BEGIN
   DECLARE MLuser VARCHAR(150);
   SELECT '>>>MLuser = ' || value INTO MLuser
      FROM #hook_dict
      WHERE name ='MobiLink user name';
   MESSAGE syncdef TYPE INFO TO CONSOLE;
END