Abstract:
Database synchronization is a complex process in heterogeneous database environment. Maintaining
the uniformity of data and its structure is a fundamental problem of data synchronization.
ODBC compliant database supports generic SQL query. Most of the ODBC compliant databases
support SQL query capturing. As a result, we can capture the SQL query from source database and
pass this SQL query to target database. We have used Oracle database as source database and any
ODBC compliant database as target database. There are many ways to capture SQL query from
Oracle database. We have used Oracle audit to capture all SQL query. Oracle audit knows what is
going on in Oracle environment. By enabling Oracle audit, we can capture all DDL and DML SQL
query which are changing the database. A process runs continuously in the back end to read SQL
query from dba_audit_trail object and passes SQL query to target system through HTTP.
Another process processes the SQL query in the target system. Some errors may happen in target
database for data type mismatch or SQL query function mismatch. To avoid these errors, we have
used two lookup tables and adapt the SQL query so that it matches the data types and query functions
of the target database. Then we have executed changed query in the target database. Hence,
the method works to keep data and database structure uniform among heterogeneous databases.
