A Guide To Oracle Change Data Capture (CDC ) Before elaborating on Oracle CDC ( Change Data Capture), let us explore what the concept of Change Data Capture is. Change Data Capture is a method that tracks and monitors changes made to a database. These include Insert, Delete, and Update, which are then stored in downstream data storage repositories to be retrieved by businesses for analytics and real - time data replication. Identifying and recording these changes helps organizations to broadcast them in real time, thereby ensuring data synchronization and minimum data latency. What is Oracle CDC The goal of Oracle CDC initially was to track and capture changes made to user tables in an Oracle database. Launched along with the 9i version of the Oracle Database Management System, these changes were to be used in ETL (Extract, Transform, and Load) applications. After processing and formatting the changes, they were to be moved to other storage capabilities such as data warehouses or other target databases. Oracle introduced an updated version of Change Data Capture with the 10g version and called it Oracle Streams. With technologically advanced features, this version was entirely different from the previous model. It combined with a replication tool built in Oracle Streams and worked in tandem with the redo logs of the source database. The advantage here was that changes made to data could be replicated to the target database without shutting down or adversely affecting the performance of the source database. This was a huge positive for large data - driven organizations, as shutting down databases even for limited periods can upset operational efficiencies. Surprisingly, despite the success of this form of Oracle CDC, Oracle chose to discontinue Oracle Streams from the release of its 12c version. Users could either choose other CDC options or pay for Oracle Golden Gate, which had Oracle CDC out of the box. The Functioning of Oracle CDC The primary function of Oracle CDC is to track and record all changes made to a database, which then helps businesses in data analytics and to make quick decisions. Apart from assisting in boosting the performance of data warehousing solutions, Oracle Change Data Capture also increases the performance of databases. As explained earlier, one of the main benefits of this feature is that databases can be replicated without any decrease in performance levels. Further, while moving databases to the cloud, there is no need to either do away with queries from the source to the target databases or shut down the source database. This is possible because the incremental data (data generated after the last round of database replication) can be extracted from different sources to be transferred to a target data repository. A very important function of Oracle CDC is to ensure that the state of the data is not compromised after changes are captured. While the entire Change Data Capture process is limited to a data warehouse environment, the process can be initiated through a database or a data storage medium. Additionally, the cost of database operation is lowered using Oracle CDC.