In this blog we are going to see about what is CDC and how to enable it in Sql Server. And some of the use cases where we need this. As a Data Engineer it is very important to know about these terms. Lets get started. In the ever-evolving landscape of data management and analysis, staying updated with real-time data changes is crucial for informed decision-making. CDC stand for Change Data Capture and it is a pivotal tool in the arsenal of a Data Engineer, enabling the efficient and seamless tracking of modifications in data, ensuring that your data pipelines remain up to date, reliable and agile.
Change Data Capture is a technique employed in the realm of data engineering that identifies and records changes made to data in a database. These changes can encompass additions, updates, or deletions, allowing for the accurate tracking of the evolving data landscape. CDC technology enables organizations to capture these changes, whether in structured relational databases or unstructured formats, such as JSON or XML.
Change Data Capture plays a critical role in various aspects of data engineering:
2) Improved Data Quality
3) Enhanced Data Replication
4) Minimizing ETL Overhead
5) Regulatory Compliance
Lets see about one by one in brief manner and let us go into the enabling the CDC.
Real-time Data Synchronization
One of the primary advantages of CDC is the ability to keep different data systems in sync in real time. In a world where data is constantly changing, businesses need up-to-the-minute information for analytics and decision-making. CDC ensures that your data warehouses and data lakes are always current.
Improved Data Quality
CDC helps maintain data integrity by recording all data changes. By capturing additions, updates, and deletions, it facilitates data reconciliation and error detection, ultimately improving data quality.
Enhanced Data Replication
CDC is instrumental for data replication, particularly when dealing with distributed systems and multi-site databases. It allows for efficient and precise replication of data across various nodes or clusters, ensuring consistency.
Minimizing ETL Overhead
Traditional ETL (Extract, Transform, Load) processes often require large-scale data transfers, leading to significant overhead and latency. CDC reduces this overhead by focusing only on changes, resulting in faster data transfers and lower resource consumption.
Regulatory Compliance
In industries with strict compliance requirements, such as finance and healthcare, CDC provides an audit trail of all data changes. This trail is invaluable for proving data accuracy and compliance with regulations.
Now let us see how we can enable CDC in Sql Server :
Step 1: Enable database for CDC
Execute the below sql command to enable the database for CDC. Here database name is "demo"
USE demo
GO
EXEC sys.sp_cdc_enable_db
GO
below is the sql server screen shot:
Step 2: Enable CDC for a table
In the below example emp is the table name .
use demo;
EXEC sys.sp_cdc_enable_table
@source_schema = N'dbo',
@source_name = N'emp',
@role_name = NULL,
@supports_net_changes = 1
GO
below is the screen shot
Step 3: Checking if the CT table is created are not.
We can check this in SSMS object explorer pane, as shown below
Do some inserts and updates to the table.
If you do a select * from the CT table you can able to see the changes happened to the table
Now let us see one of the common and important scenario. We can introduce kafka here, using kafka connect we can connect with SSMS and the consumer can be multiple groups. So the kafka brokers will contain only the data where the changes happened. So with that we can develop our data warehouse. Note in this scenario we need to use some of the connectors like debezium connector , which will directly see the table logs and only pick the changes.
Thus in this blog we saw about the what is CDC and how we can enable it in SSMS via step by step screenshots. And also we saw one of the important real time scenario, Hope this blog is usefull.
Thank You !!!
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