can i have a trigger which will update fields in another database? and if yes, does such an approach has got some performance issues?

Yes you can do that and without any performance issue. Here is the syntax
<DatabaseName>@<InformixServerName>:<TableName>

adityanlal

Be careful with "no performance issues." The problem can be that triggers are executed a lot, and can trigger a whole lot more updating-activity than you really want or need. It doesn't "scale up" very well.

The general term for this process is "replication," and it's often desirable for the actual activity that updates the slave database to be executed by a separate (daemon, or scheduled) process that runs periodically. It selects those records which are marked (in some way) as "changed," and executes the queries on the slave database to bring the records in-sync. Record-deletion is obviously a different sort of problem.

Also bear in mind that "replication is a problem that has been thoroughly studied and solved." Maybe there is a product already out there that's designed to do this and which will solve-the-problem a whole lot quicker and more effectively than a home-grown cobblestone solution. It's worth looking at.

You can do this to some degree with triggers since your SQL is limited. But they can call Stored Procedures which give you increased flexibility.

But, both DB's must be the same logging mode.