IBM InfoSphere Federation Server, Version 10.1

What is an update in a federated system?

In a federated system, an update is not just a transaction that includes an INSERT, UPDATE, or DELETE statement. There are certain operations that are considered updates in a federated system and certain types of updates that are allowed in federated system.

In a federated system, updates can be performed locally or remotely.

Local site updates are updates to DB2® tables or views that do not reference nicknames
Remote site updates are updates to objects on a remote data source. Remote data sources include:
- Another DB2 Database for Linux, UNIX, and Windows database or instance on the federated server
- Another DB2 Database for Linux, UNIX, and Windows database or instance on another server
- Data sources other than DB2 Database for Linux, UNIX, and Windows, such as DB2 for System i®, Informix®, Oracle, and Teradata

There are four types of actions that the federated server considers to be update transactions. The following table shows the updates that you can perform on a federated system.

Table 1. Types of updates and the site where the updates are performed
Type of action	Local site	Remote site	Explanation
Local update (DDL and DML)	Y	N	An update on an object in the federated database.
Remote update (nickname)	N	Y	An update on a remote data source object that you created a nickname for.
Dynamic SQL in pass-through sessions	N	Y	An update on a remote data source object. You cannot use a pass-through session to update local objects. Even SELECT queries sent in pass-through sessions are considered to be an update action.
Transparent DDL	Y	Y	A pair of transactions that create, alter, or drop remote tables and their corresponding nicknames in a federated database. For example, a pair of transactions that create a remote table on a data source and a nickname on the federated server.

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Last updated: 2012-05-18