What is Change Data Capture (CDC)? Tools and examples (2023)

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Data is growing everywhere. Experts predict that in 2025the global amount of data will amount to 181 zettabytes, or more than four times 2019 pre-Covid levels. Data is inevitable in every aspect of life – and this is doubly true in business. In a world changed by COVID, the business world is a world of data.

But it can seem like for every problem that data solves, another emerges: saturated and isolated data streams make it difficult to make meaningful connections between data sets. New data gives us new opportunities to solve problems, while maintaining the freshness, quality and relevance of the datamy dateidatawarehousesis an endless effort. And despite the proliferation of machine learning and automated solutions, much of our data analysis is still the product of inefficient, mundane, and manual tasks.

When you add it all up, organizations need to extract the most value from their data, and they need to do it in the most scalable way possible. To support this goal, data integrators and engineers need a real-time data replication solution that helps them avoid data loss and ensure data is current in all use cases. and multi-cloud environments and increase the agility of your business.

Change Data Capture (CDC) allows data to be quickly replicated from source applications to any destination, without the tedious engineering work of extracting or replicating entire data sets. This ensures that organizations always have access to the latest, most up-to-date data.

Change the data logging definition

Change commit refers to the process of identifying and committing changes as they are made to a database or native application, then propagating those changes in real time to a downstream process, system, or data lake.

This advanced data replication and loading technology reduces the time and resource costs of data warehousing programs and enables real-time data integration across the enterprise. By detecting changed records in data sources in real time and communicating those changes to the ETL data warehouse, change data capture can dramatically reduce the need for bulk warehouse updates.

CDC is increasingly the most popular form of data replication because it only sends the most relevant data, reducing the burden on the system. And because CDC only imports data that has changed -- rather than replicating entire databases -- CDC can dramatically speed up data processing and enable real-time analytics.

What is data replication and why is it important?

Data replication is exactly what it sounds like: the process of simultaneously making copies and storing the same data in multiple locations. Establishing this kind of redundancy for your database systems offers a wide range of benefits while improving data availability and accessibility, as well as system resiliency and reliability.

(Video) Change Data Capture (CDC) Explained (with examples)

Data replication ensures that you always have an accurate backup in the event of a disaster, hardware failure or system breach. And having a local copy of important datasets can reduce latency and lag when global teams work from the same source data, for example in Asia and North America.

When it comes to data analytics, there is another layer for data replication. Data-driven organizations often replicate data from multiple sources into data warehouses, where they use it to power business intelligence (BI) tools.

However, like any system with redundancy, data replication can have its drawbacks. When there are updates to data stored in multiple locations, they should be updated system-wide to avoid conflicts and confusion. This can double (or triple) the growth of data management over time and puts a strain on resources, forcing data integrators and engineers to monitor multiple systems and databases or periodically replicate an entire database from source systems to all other systems, applications . and data lakes or data warehouses that use the same data sets.

CDC mitigates this increase by replicating only new data or data that has recently changed, giving users all the benefits of data replication without the drawbacks.

How does the GGD work?

With new data coming in all the time and existing data constantly changing, data replication becomes more and more complicated. Because it works continuously rather than sending updates in bulk, CDC provides organizations with faster updates and more efficient scaling as more data becomes available for analysis.

However, not all CDC implementations are identical - or provide identical benefits. Let's take a look at the three CDC methods and explore the benefits and challenges of each:

Script-based CDC

It is possible to build a CDC solution on an application by writing a SQL-level script that monitors only key fields within the database. When there is a change to that field (or fields) in the source table, it serves as an indicator that the row has changed. The modified rows can then be replicated to the destination in real time, or they can be replicated asynchronously during a scheduled bulk load.

The script-based method is quite simple, but creating and maintaining a script can be challenging, especially in a rapidly changing or constantly changing data environment. For an effective script, it may be necessary to change the schema, such as adding a date/time field to indicate when a record was created or updated, adding a version number to log files, or enabling a Boolean status indicator.

(Video) What is Change Data Capture?

Since the script only looks at selected fields, data integrity can be an issue if there are changes to the table schema. And while CDC still requires fewer resources than many other replication methods, by retrieving data from the source database, CDC can add additional load to the system.

CDC based on triggers

Instead of writing an application level script, another CDC solution looks for database triggers. Triggers are functions written in software to record changes based on certain events or "triggers". Most triggers fire when there is a change to the source table, using SQL syntax such as "BEFORE UPDATE" or "AFTER INSERT".

This method gives developers control because they can define triggers to commit changes and then generate a change log. And because triggers are reliable and specific, data changes can be recorded in near real-time.

However, there are some drawbacks to the approach. The first is obvious: since triggers must be defined for each table, downstream problems can occur when the tables are replicated. The reliability of this solution can also be compromised if, for example, users can intentionally disable triggers or enable certain operations.

In addition, with each transaction, a change record is created in a separate table, as well as in the database's transaction log file. Because it has to intermittently go to the source database, trigger-based CDC adds additional load to the system and can negatively impact latency.

Log-based CDC

The most efficient and effective CDC method is based on an existing feature of corporate databases: the transaction log. In a typical corporate database, all data changes are tracked in a transaction log. In the event of a disaster or system crash, data can be reconstructed from these transaction logs.

CDC's log-based solution monitors the transaction log for changes. When those changes happen, they are pushed to the destination data store in real time.

Because there are transaction logs to ensure consistency, log-based CDC is extremely reliable and records every change. And since the transaction logs exist separately from the database records, there's no need to write additional procedures that put extra strain on the system, meaning the process doesn't affect the original database's transaction performance. Best of all, continuous log-based CDC operates with extremely low latency, monitoring changes in the transaction log and sending those changes to the destination or target system in real time.

(Video) MSSQL - How to, Step by Step Change Data Capture (CDC) Tutorial

But because log-based CDC takes advantage of the transaction log, it is also subject to the limitations of that log file - and log formats are often proprietary. As a result, log-based CDC only works with databases that support log-based CDC. However, given all the advantages in terms of reliability, speed and price, this is a small disadvantage.


Today, the average organization draws on more than400 data sources. When you rely on so many different sources, the data you get has to be in different formats or rules. Moving as is from a data source to a target system via simple APIs or connectors would likely lead to duplication, confusion, and other data errors.

ETL — which stands for Extract, Transform, Load— is a key technology for bringing data from multiple disparate data sources into one centralized location. As the name implies, this technology takes data from a source, transforms it according to an organization's standards and norms, and then loads it into a data lake or data warehouse, such as Redshift, Azure, or BigQuery.

Without ETL, it would be nearly impossible to turn massive amounts of data into actionable business intelligence. But when the process relies on bulk-loading the entire source database into the target system, it consumes a lot of system resources, making ETL impractical at times - especially for large datasets.

That's where the CDC comes in. Because the CDC process uses only the latest, newest, most recently changed data, the ETL system takes a lot of the pressure off. Essentially, CDC optimizes the ETL process.

At the same time, ETL can compensate for the primary weakness of log-based CDC. Unlike CDC, ETL is not limited by proprietary log formats. This means it can replicate data from any source, including data that cannot be replicated through log-based CDC.
In short, CDC and ETL are complementary technologies: CDC makes ETL more efficient and ETL captures all data sources that log-based CDC cannot capture.

Use cases of CDC technology

Because CDC gives organizations real-time access to the latest data, the applications are almost endless. With change data collection technology like Talend CDC, organizations can address some of their most pressing challenges:

Get the right data in the right hands in the right formats

It's not enough to just have data - that data needs to be accessible. CDC makes it easy to create, manage, and maintain data pipelines for use across an organization. This means all users have access to the most up-to-date and accurate data for business intelligence, reporting and direct use in analytics and applications.

(Video) What is Event-driven Change Data Capture Process?

Increase the accuracy, quality and reliability of data

CDC's real-time, low-touch replication of data removes the most common barriers to reliable data. A data lake or data warehouse is guaranteed to always have the latest, most relevant data. This allows users to be more confident in their analytics and data-driven decisions.

Improve regulatory compliance and adherence to privacy standards

Compliance with regulatory standards isn't as easy as it sounds: When an organization receives a request to remove personal information from its databases, the first step is to locate that information. If a claimant has multiple related logs across multiple applications, for example, web forms, CRM, and in-product activity logs, compliance can be a challenge.

By keeping the data current and consistent, CDC makes it easy to find and manage that data, protecting both the business and the consumer.

Extensive business data integration

Talend CDC helps reach customershealth dataEnabling data teams to robustly and securely replicate data to increase data reliability and accuracy. Our proven enterprise-grade replication capabilities help businesses avoid data loss, ensure data freshness, and achieve desired business outcomes.

Talend's change data capture feature works with a wide variety of source databases.

Talend data integrationprovides end-to-end support for all aspects of data integration and management in a single platform. With an intuitive development environment, users can easily design, develop and implement processes for database conversion, data warehouse loading, real-time data synchronization or any other integration project.

In addition to advanced runtime features such as change data capture, Talend's data warehousing tools include support for advanced ETL testing, with features such as context management and remote task execution. The system also offers enterprise-class functionality such as workflow collaboration tools, real-time load balancing, and support for innovative mass storage technologies such as Hadoop.

In addition to our superior functionality, Talend offers professional technical support from Talend data integration experts. For organizations launching master data management initiatives, Talend also offersMDM solutionthat integrates seamlessly with Talenda.

(Video) Handling changes in Data in Bigdata world |Change data capture| SCD Types

Learn more about Talentdata integration solutionstoday and take advantage of the leading open source data integration tool.


What are change data capture tools? ›

Change data capture (CDC) is a process that enables organizations to automatically identify database changes. It provides real-time data movements by capturing and processing data continuously as soon as a database event occurs.

What are CDC tools? ›

CDC tools enable companies to replicate data to an analytical database that analysts can query without overloading operational databases. In short, CDC tools help you create a more modern data stack. But you need to choose one that can support your business requirements.

What is change data capture CDC and how does it work? ›

Change Data Capture is a software process that identifies and tracks changes to data in a database. CDC provides real-time or near-real-time movement of data by moving and processing data continuously as new database events occur.

What is CDC and how it works? ›

As the nation's health protection agency, CDC saves lives and protects people from health threats. To accomplish our mission, CDC conducts critical science and provides health information that protects our nation against expensive and dangerous health threats, and responds when these arise.

What are examples of data capture? ›

Many other data capture methods exist, including magnetic stripe cards, Optical Mark Reading, Magnetic Ink Character Recognition, smart cards, video/image capture, and more. However, these are the most common methods used today.

What are the different types of change data capture? ›

There are multiple types of change data capture that can be used for data processing from a database. These include log-based CDC, trigger-based CDC, CDC based on timestamps and difference-based CDC.

What is CDC in simple terms? ›

The CDC works with state health departments and other organizations throughout the country and the world to help prevent and control disease. The CDC is part of the U.S. Public Health Service of the Department of Health and Human Services (DHHS). Also called Centers for Disease Control and Prevention.

What CDC means? ›

CDC – Centers for Disease Control and Prevention.

What does CDC data stand for? ›

Change data capture (CDC) refers to the tracking of all changes in a data source (databases, data warehouses, etc.) so they can be captured in destination systems. In short, CDC allows organizations to achieve data integrity and consistency across all systems and deployment environments.

How is CDC different from ETL? ›

Before CDC technology, ETL could only extract data in bulk which slowed down the process and didn't always provide accurate real-time information. However, CDC captures and delivers even the tiniest changes made to the data, step-by-step, in real-time. For this reason, it brings many benefits to ETL pipelines.

What is change data capture in SQL? ›

Change data capture (CDC) uses the SQL Server agent to record insert, update, and delete activity that applies to a table. This makes the details of the changes available in an easily consumed relational format.

What is CDC and how have you applied CDC technique? ›

It allows Data Warehouse or Databases to stay active for some action to perform as soon any Change Data Capture occurs. CDC is a Data Integration approach that allows high-velocity data to achieve reliable, low latency, and scalable data replication using fewer computation resources.

What kinds of threats does the CDC prevent? ›

A disease threat anywhere is a disease threat everywhere. CDC's Global Health Center works to protect Americans from dangerous and costly public health concerns, including COVID-19, vaccine-preventable diseases, HIV, TB, and malaria—responding when and where health threats arise.

What is the purpose of the CDC and when was it created? ›

On July 1, 1946 the Communicable Disease Center (CDC) opened its doors and occupied one floor of a small building in Atlanta. Its primary mission was simple yet highly challenging: prevent malaria from spreading across the nation.

What are 4 devices that capture data? ›

Some common types of data capture devices are barcode readers and scanners, magnetic stripe readers, signature capture pads, fingerprint capture devices, and ID scanners.

What are the 4 stages of data capture? ›

The data collection process in four stages: (1) Identification, (2) Unification, (3) Verification, and (4) Enrichment.

What are the three methods of data capture? ›

The most appropriate data capture method depends on the nature of data to be captured and the application area.
  • Manual Keying. ...
  • Nearshore keying. ...
  • OCR (Optical Character Recognition) ...
  • ICR (Intelligent Character Recognition) ...
  • Barcode/ QR recognition. ...
  • Template based intelligent capture. ...
  • IDR (Intelligent Document Recognition)

What are the two main types of data capture? ›

The two main types of data capture are manual and automated. Manual data capture involves manual input of information from physical forms into computer systems. Automated data capture uses software tools to extract data from digital sources.

What is CDC in Salesforce? ›

Change Data Capture is a streaming product on the Lightning Platform that enables you to efficiently integrate your Salesforce data with external systems. With Change Data Capture, you can receive changes of Salesforce records in real time and synchronize corresponding records in an external data store.

What is CDC pattern? ›

In databases, change data capture (CDC) is a set of software design patterns used to determine and track the data that has changed (the "deltas") so that action can be taken using the changed data.

What is the CDC main function? ›

Our job is to prevent, detect, and respond to diseases wherever they are so that diseases don't come into the United States. CDC provides domestic and international leadership, as well as laboratory and epidemiology expertise, to respond and work toward eliminating every disease we can.

How do you use CDC in a sentence? ›

The Centers for Disease Control and Prevention (CDC) reports that the number of deaths from pneumonia in the United States declined between 2001 and 2004. According to the Centers for Disease Control and Prevention (CDC), up to 33 million cases of food poisoning are reported in the United States each year.

What impact does the CDC have on standards of care? ›

CDC detects and controls outbreaks at their source, saving lives and reducing healthcare costs. Importantly, CDC helps other countries build capacity to prevent, detect, and respond to their health threats through our work.

What is data capturing? ›

Data capture is the process of extracting information from paper or electronic documents and converting it into data for key systems. It's where most organizations begin their information management and digital transformation journey.

How do I get data from CDC? ›

E-mail: cdcinfo@cdc.gov. Tel: 1–800–232–4636. Website: http://www.cdc.gov/nchs. The NCHS website is designed to provide users with quick and easy access to the wide range of information and data available from NCHS.

How do you reference CDC data? ›

Author's name, last name first and initials. Name of report. National health statistics reports; and number. Hyattsville, MD: National Center for Health Statistics.

Is the CDC a database? ›

CDC's WISQARS™ (Web-based Injury Statistics Query and Reporting System) is an interactive, online database that provides fatal and nonfatal injury, violent death and cost of injury data from a variety of trusted sources.

How do I set up change data capture? ›

To enable change data capture, run the stored procedure sys. sp_cdc_enable_db (Transact-SQL) in the database context. To determine if a database is already enabled, query the is_cdc_enabled column in the sys. databases catalog view.

What is the purpose of change data capture process in ETL? ›

Change data capture (CDC) is a process that captures changes made in a database, and ensures that those changes are replicated to a destination such as a data warehouse.

What is the difference between CDC and SQL replication? ›

In simple words, MS Replication will hold transactions in Tlog, and Replicate can read those transactions from Tlog before they got truncated\archieved. To use MS replicate your tables must have PK. Whereas MS CDC will maintain the transactions in change tables and Replicate can read data from these change tables.

What is the difference between CDC and change tracking in SQL? ›

SQL Server provides several mechanisms to track changes in a database: Change Tracking: This is a lightweight mechanism for tracking changes to individual rows in a database. Change Data Capture (CDC): This is a more comprehensive mechanism for tracking changes to data, including inserts, updates, and deletes.

What is the disadvantage of using change data capture? ›

Disadvantages: They run as part of the operational transaction, slowing it down. Even worse, it makes them disruptive – if they run into an unexpected error and throw an exception, the user transaction will fail, breaking the operational system.

How to use SQL CDC? ›

How to enable CDC in SQL Server – step by step
  1. At DB level: Use <databasename>; EXEC sys.sp_cdc_enable_db; For Example: Use Adventureworks2019; EXEC sys.sp_cdc_enable_db;
  2. At table level: USE <databasename> GO. EXEC sys.sp_cdc_enable_table. @source_schema = '<schema_name>', @source_name = '<table_name>', @role_name = null,

How do you implement CDC in SQL? ›

To enable CDC on a SQL Server table, you need to first enable it at the database level and then enable it on the specific table. Once enabled, SQL Server will automatically create a separate table to store the changes. CDC uses a special type of table called a change table to store the captured changes.

What is the difference between change data capture and SCD? ›

Change Data Capture (CDC) quickly identifies and processes only data that has changed and then makes this changed data available for further use. A Slowly Changing Dimension (SCD) is a dimension that stores and manages both current and historical data over time in a data warehouse.

What are 3 examples of standard precautions according to CDC? ›

Standard Precautions
  • Hand hygiene.
  • Use of personal protective equipment (e.g., gloves, masks, eyewear).
  • Respiratory hygiene / cough etiquette.
  • Sharps safety (engineering and work practice controls).
  • Safe injection practices (i.e., aseptic technique for parenteral medications).
  • Sterile instruments and devices.

What are the six CDC risk factors? ›

These include sexual behaviors, substance use, suicidal thoughts and behaviors, experiences such as violence and poor mental health, social determinants of health such as unstable housing, and protective factors such as school connectedness and parental monitoring .

What are the five risk factors identified by the CDC? ›

Prevention (CDC) have identified the top 5 factors contributing to foodborne illnesses:
  • Poor Personal Hygiene. Poor personal hygiene practices serve as the leading cause of foodborne illnesses. ...
  • Improper Holding Temperatures. ...
  • Improper Cooking Temperatures. ...
  • Food from Unsafe Sources. ...
  • Contaminated Equipment/Cross-Contamination.

What is the purpose of the CDC and prevention? ›

The Centers for Disease Control and Prevention (CDC) serves as the national focus for developing and applying disease prevention and control, environmental health, and health promotion and health education activities designed to improve the health of the people of the United States.

What are the core values of the CDC? ›

Through CDC's core values (accountability, respect, and integrity); agency employees affirm that they are honest and ethical in all that they do, and that they prize scientific integrity and professional excellence.

What are the accomplishments of the CDC? ›

CDC has contributed to major advances in vaccine development and testing for flu, West Nile virus, dengue, Japanese encephalitis, Rift Valley fever, rotavirus, polio, meningitis A, pneumococcus, pertussis, HIV, hepatitis E, tuberculosis, and human papilloma virus.

Which tool can be used to capture data? ›

Optical mark reading (OMR) technology is designed to capture human marked data from documents such as forms and surveys. The intelligent technology has the ability to differentiate between marked and unmarked boxes.

What are 3 examples of devices that collect your personal data? ›

Think about your smart thermostat, your WiFi connected washers and dryers, your Ring video doorbells, and your internet-enabled refrigerator. If you've ever logged in to interact with these devices, then they could be collecting data about you.

What is data capture methods? ›

Data capture is the process of extracting information from any type of structured or unstructured document (paper or electronic) to transform it into a machine-readable digital format. Technological advancements in the field of Artificial Intelligence (AI) have taken data capture to new heights.

What do you mean by data capture? ›

Data capture is the process of extracting information from paper or electronic documents and converting it into data for key systems. It's where most organizations begin their information management and digital transformation journey.

What are the 5 common ways to collect data? ›

What Are the Different Methods of Data Collection?
  • Surveys.
  • Transactional Tracking.
  • Interviews and Focus Groups.
  • Observation.
  • Online Tracking.
  • Forms.
  • Social Media Monitoring.
6 days ago

What is the best tool for data processing? ›

Let's talk about some of the best data processing software tools on the market:
  1. Google BigQuery. One of the best data processing software is Google Big Query. ...
  2. Amazon Web Services. ...
  3. Hortonworks. ...
  4. Cloudera.
Feb 22, 2023

Where is data capture used? ›

Automated data capture is typically used in the banking industry to: Process banking documents such as account opening forms, bank statements, tax statements, credit card applications, fund transfer applications, and much more.

What are two tools that can help you record data? ›

What Are Data Collection Tools?
  • Interviews.
  • Questionnaires.
  • Case Studies.
  • Usage Data.
  • Checklists.
  • Surveys.
  • Observations.
  • Documents and records.
Oct 31, 2022

What is the difference between data collection and data capture? ›

Collection also includes the extraction of information from administrative sources which may require asking the respondent permission to link to administrative records. Data capture refers to any process that converts the information provided by a respondent into electronic format.

What is the difference between data entry and data capture? ›

What is the difference between data capture and data entry? Data capture is used on data sources that contain basic response types like multiple choice, “yes-no” and bubble circles, whereas, data entry is the input and storage of text and numbers from a document into an electronic system.


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