Db2 – List of open (uncommitted transactions) in DB2 LUW

Actually, on the link you have, it mentions that you can update only one record, you just have to use cursors to do so. It then points you to the DECLARE CURSOR page.

So first, you would have to declare a cursor from your table with the select statement that would give you what you want.

DECLARE C1 CURSOR
FOR (SELECT * FROM MYTABLE WHERE...);

Move to the value of the record in the cursor that you want.

Then run you update statement against the cursor using the link you mention

UPDATE MYTABLE 
SET MYCOLUMN = ?
WHERE CURRENT OF C1;

I believe you need to issue a COMMIT (which closes the cursor unless you specify otherwise in the DECLARE CURSOR clause).

Check out the documentation in the link you have and in the one I have. You may end up having to use a stored procedure to run this.

Yes this can be done but you need a third party acting as a transaction coordinator. The standard protocol for this is called Two Phase Commit (2PC). This is usually done with a transaction manager acting as the coordinator.

This can also be generalized further to more than two databases. In fact it doesn't even have to be databases as the approach is generally applied to "transactional resources". Besides databases the other common transactional resource is a message queue. The usual example is to perform some work in a database (ex: update an account balance) and also send a message out on a message queue (ex: an outbound order).

For this to work your datasources need to support 2PC, usually via the XA protocol. How to do it depends on the specific type of datasource and programming language (ex: for Java you'd use an XADataSource).