An upload subscription is a type of JDBC subscription that allows you to insert rows directly into a table on a source database. An upload subscription defines a one-way synchronization from mobile devices to a source database. Normally, no data is sent from the source database to a mobile device during synchronization and refresh. The only exception is that reject notifications are sent to mobile device in the case where some rows failed to be inserted into the source database. In this case, the mobile device is notified that the problematic rows have been rejected by the source database.
The source table can reside on any database that supports JDBC. Upload subscriptions can improve Sync Server's throughput, simplify administration, and increase system reliability.
Upload subscriptions can be used in scenarios where the client devices are used only for collecting data only. Such scenarios include:
There are few restrictions on the source database except that it must support JDBC and SQL INSERT statements. Because there is no replication for an upload subscription, the burden on the Sync Server is alleviated.
In an upload subscription, when you synchronize with the Sync Server, the DB2 Everyplace database engine on the handheld device communicates directly with the source database to insert the rows that have been added to the DB2 Everyplace database. The flow of the data is one-way; the tables on the device are not refreshed. No mirror database is involved in this process.
If a primary key is used, multiple inserts that cause a primary
conflict are rejected. The rejections are logged in both the client and
the Mobile Devices Administration Center (MDAC) on the Sync Server.
Other operations, like DELETE and UPDATE, are either ignored by the source
database or rejected. Table 206 lists client operations and results.
Table 206. Client's possible operations and their consequences
| Operation | Results |
|---|---|
| Client's INSERT operations without conflicts in the primary key | Inserted into the source database |
| Client's INSERT operations with conflicts in the primary key | Rejected with error messages logged in the client and the MDAC |
| Client's UPDATE operations | Rejected with error messages logged in the client and the MDAC |
| Client's DELETE operations | Ignored silently |
| First-time synchronization | Tables created in the client with no rows |
Use the Create Upload Subscription notebook to create an upload table subscription. See Creating an object from the object tree for information on how to open the notebook. Each table subscription that you create can reference one or more tables.
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