Oracle Change Data Capture

1. Oracle CDC and the Evolution of the Technology

2. CDC (Change Data Capture) is primarily software design patterns that are used to monitor changes in input in a source database. Based on these changes, specific action is taken at a later stage. Apart from capturing data at the source, CDC also includes data identification and data delivery of all the changes made at source across enterprise database networks. 

4. Oracle Change Data Capture ensures that data is integrated in real-time across the networks in organizations, thereby helping to improve the performance and availability of databases and speeding up all activities of data warehousing solutions. This advanced technology is used in conjunction with cutting-edge tools and efficient non-intrusive methods to perform critical replication activities without any lag or performance degradation of source or target databases.  • Some of the other tasks that can be carried out with Oracle Change Data Capture is divesting analytics queries from databases in production to data warehouses and migrating databases to the cloud. All these tasks are done without any stoppage in work or downtime. 

5. An important function of Oracle Change Data Capture is capturing and preserving the data form. This is done in a data warehouse environment that also doubles up as a data repository system. This makes the work of setting up the Oracle CDC mechanism easy. Developers can launch application logic to physical storage in a single or multiple groupings of system layers.  • The Oracle Change Data Capture technology was first introduced by Oracle in their Oracle 9i version database. It could monitor and record all changes in user databases. These changes were then stored in changed tables for later use in ETL applications. The CDC concept at that time was based on creating triggers in the source tables, a process that was tedious and did not find favor with the Database Administrators. • Oracle released a modified model of Oracle Change Data Capture with their 10g version, and this time, the technology was well-received by the DBAs. This system leveraged the redo logs in the source database as against set triggers previously. This in-built tool was called Oracle Streams. It was seen as a major improvement over the earlier technology as it could detect and move changed data to another target data source without adversely affecting the performance of the database at the source. • However, even though this model of Oracle CDC found favor across developers and organizations, Oracle discontinued Oracle Streams after their release of Oracle 12c, and users had to pay for Oracle Golden Gate to avail Oracle CDC.  • In the current Oracle Change Data Capture structure, when data in the source database changes, another database, known as the target database has to take some action based on those changes. The two are generally different but even when they are the same, Oracle CDC works just as efficiently. Hence, several CDC solutions in sync are seen within the same system.