Change Data Capture (CDC) is a method of identifying and capturing changes made to a database. It captures data changes and enables businesses to keep track of all modifications made to their data, including updates, inserts, and deletes. CDC is a critical tool for businesses, particularly those who deal with large volumes of data, as it allows them to make better decisions by providing analysis. In this article, we will discuss CDC, its benefits, how it works, and its importance.
How CDC Works
CDC works by capturing changes made to a database and forwarding them to a target system. It uses log files to capture changes made to the database. The log files are generated by the database management system and contain information about every change made to the database. CDC monitors the log files and captures the changes made to the database in real-time or batch.
Once CDC captures the changes, it forwards them to the target system. The target system can be another database or a data warehouse, where the captured data can be used for further analysis. The target system can also be an application that uses the captured data to update its own database or provide real-time analytics.
CDC can be implemented in two ways — trigger-based and log-based.
Trigger-based CDC
Trigger-based CDC works by attaching triggers to database tables. A trigger is a set of instructions that executes when a specific event occurs. In the case of CDC, the trigger is set to execute when a change is made to a table. The trigger captures the changes made to the table and forwards them to the target system.
Trigger-based CDC is commonly used in small databases or databases with low data volumes. It is also used in scenarios where there is a need for selective data capture, as triggers can be set up to capture changes made to specific tables.
Log-based CDC
Log-based CDC works by monitoring the log files generated by the database management system. The log files contain information about every change made to the database, including updates, inserts, and deletes. CDC monitors the log files and captures the changes made to the database in real-time.
Log-based CDC is commonly used in large databases or databases with high data volumes. It is also used in scenarios where there is a need for complete data capture, as it captures all changes made to the database.
Benefits of CDC
CDC has several benefits for businesses, including:
- Real-time data capture: CDC captures changes made to the database in real-time, allowing businesses to have up-to-date information.
- Improved data accuracy: CDC captures all changes made to the database, reducing the risk of errors and ensuring data accuracy.
- Reduced data latency: CDC captures changes in real-time, reducing data latency and providing faster access to data.
- Increased productivity: CDC automates the process of capturing data changes, reducing manual effort and increasing productivity.
- Better decision-making: CDC provides businesses with real-time data, allowing them to make better decisions.
CDC can be used in various scenarios, including:
- Data integration: CDC can be used to integrate data from multiple sources in real-time.
- Data warehousing: CDC can be used to capture changes made to a database and forward them to a data warehouse for further analysis.
- Data migration: CDC can be used to migrate data from one database to another in real-time.
- Business intelligence: CDC can be used to provide real-time analytics and reporting.
Importance of CDC
CDC is essential for businesses that deal with large volumes of data. It allows businesses to keep track of all data changes in their database and provides real-time data for decision-making. CDC is also important for compliance with regulatory requirements, as it provides an audit trail of all data changes.
CDC is an essential tool for data warehousing, data integration, and data analytics. Without CDC, businesses would struggle to keep up with the constant changes made to their data and would have to rely on manual effort to capture these changes. This can lead to delays in decision-making and inaccuracies in data analysis.
Another benefit of CDC is that it can help businesses to identify and address data quality issues. By capturing all changes made to the database, CDC can identify patterns of data quality issues and enable businesses to take corrective action.
Overall, CDC is a critical tool for businesses that need to keep track of changes made to their data in real-time. It provides real-time data for decision-making, reduces data latency, improves data accuracy, and increases productivity. CDC can be implemented in various scenarios, including data warehousing, data integration, data migration, and business intelligence.
Example of CDC in Action
To better understand how CDC works, the image above state a CDC log table created by Snowflake Streams, that capture CDC in REAL TIME. There are 3 metadada columns that states what happened to the data, and based on it, we can take actions manually or automatically.
Conclusion
In conclusion, Change Data Capture (CDC) is a critical tool for businesses that need to keep track of changes made to their data in real-time. CDC provides real-time data for decision-making, reduces data latency, improves data accuracy, and increases productivity. CDC can be implemented in various scenarios, including data warehousing, data integration, data migration, and business intelligence. The two main types of CDC are trigger-based and log-based. Trigger-based CDC is commonly used in small databases or databases with low data volumes, while log-based CDC is commonly used in large databases or databases with high data volumes. With CDC, businesses can ensure that they have up-to-date and accurate information to make informed decisions.
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