We propose a database transaction management framework that enables a database replication function to be added to existing cluster systems. This framework is generally applicable to various database products merely by replacing the database connection API library. In this framework, the enhanced database connection API library duplicates the transactions issued by clustered applications and issues them to the primary and backup databases while controlling the issue order for consistency between the two databases. We implemented the proposed framework on a database connection API library for Java and confirmed that the overhead caused by duplication and order control was smaller than the existing replication method's overhead.