How to synchronize tables between several (at least two) database ?
I have DB1, DB2, DB3.... which contains table A, table B ...
As long as I Modify table A in any of the DB, then the table A in all the rest DB should be syncronized. same for table B, (but not whole database)...
There is no master and slave database, all DB (could be in different server)should be running.
Is there any mechenism for informix to do synchronize only on table level?
Or i am obliged to use trigger statetments on each table on update, delete, and insert ,then launch the trigger action in other DBs to do the same update, delete, insert? Is there simple solution?

Yes there is a way. Its called Enterprise Replication (update anywhere).

but as i understand enterprice replicate is for database in two server? (how about database in one server?), and it is for whole database (more for migration), could take a a lot of storage, even slow down the process...

As long as the databases are located in different instances, you can set-up enterprise replication. Even they are located in the same server. You can even set-up HDR on the same server and different instances.

Then could I set up the entreprise replication server only for certain tables in the database, but not for the whole database?

Well, seems it can work on a group of tables. But another question,
if in DataBaseA, it is updating the same records as on DataBase B, how could I detect the conflict immediately?

Yes. You add tables to replicate.

You define your conflict resolution in you Enterprise Replication.

Unfortunately the enterprise replication solution is nearly refused, the reason is it cause a lot of problem. Well, i have never worked on update anywhere replication. Does it really has a lot of hidden problem? performance, space ? for only 6 tables which doent have a lot of transactions without big volumn of data?