Essential Elements of Oracle Change Data Capture

 

Change Data Capture is a software pattern used for tracking and capturing changes made to a database. Types of changes include insert, delete, and update, which are stored in downstream systems. 



Oracle launched its Oracle Change Data Capture product with its 9i version. Its core function was to track and capture deletes, updates, and inserts made to user tables in an Oracle database to be used in ETL applications. These changes were then processed, formatted, and moved to other storage repositories such as target databases or data warehouses.

The function of Oracle Change Data Capture is to track and record all changes made in a database. These are used by businesses for analytics and to make fast and optimized operational decisions. Oracle CDC also boosts database performance and increases the speed of data warehousing operations.

What sets Oracle Change Data Capture apart from others in this niche is that it helps to replicate databases without adversely impacting their performance in any way. Source systems need not be shut down when using CDC for moving databases to the cloud. This is possible as any data generated after the last replication run (incremental data) can be extracted from several sources to be transferred to a data warehouse.

Types of Oracle Change Data Capture

There are two types of Oracle Change Data Capture

Synchronous Mode

In this type of Oracle Change Data Capture, triggers placed in the source database are automatically set off when any change is identified. Each SQL statement carries out a DML (Data Manipulation Language) activity classified as Insert, Update, or Delete.

Asynchronous Mode

This type of Oracle Change Data Capture functions through redo logs. These logs move the data with changes captured only after a SQL statement starts a DML activity. The changed data does not affect the transactions in any way. The three versions of the Asynchronous Mode are HotLog, Distributed HotLog, and AutoLog.

Both modes are fully automated, and businesses can choose any of the Oracle Change Data Capture types. 

Comments

Post a Comment

Popular posts from this blog

SQL Server Change Data Capture – A Comprehensive Overview

Image
  Microsoft launched its SQL Server CDC product in 2005 with several cutting-edge and technologically advanced features, such as “after update”, “after insert”, and “after delete” abilities. Since this technology was very complex and not received well by DBAs, Microsoft released a revised and more advanced version of the SQL Server CDC in 2008, which became very popular and is still in use today. The Concept of SQL Server Change Data Capture SQL Server CDC captures and records changes made in the source database, such as “Insert”, “Update”, or “Delete”. These can be accessed by any user seamlessly, with all details available in an easy-to-understand relational format. CDC provides all the information required for capturing the changes to an intended target. The data for modified and changed rows is available in CDC. The changes made are stored in tables and are reflected in the structure of the tracked source tables. For data security, access to the table-valued functions of ...
Read more

What is SQL Server Change Data Capture – Evolution and Function

Image
  The goal of SQL Server CDC is to capture any changes made in a source database and present them to users in a simple relational format. Types of changes include insert, update, and delete to the database. All inputs required to capture these changes to the target, such as column information and metadata, are available for the modified and changed rows. After the changes are made and noted in the tables at source, they are replicated in the column information of the target tables. As a matter of database safety and security, access to the changes is monitored closely. Development of SQL Server CDC It was in 2005 that Microsoft launched SQL Server CDC with “after update”, “after insert”, and “after delete” features. However, DBAs found its working quite complex. Based on this feedback, Microsoft introduced a revised version in 2008, which was very user-friendly, well-received, and is still in use today. In this version, database administrators can capture and store changes ma...
Read more

An Overview Of Moving Databases From Oracle to SQL Server

Image
  Let us start with why you should migrate databases from Oracle to SQL Server.  Benefits of Oracle to SQL Server database migration   Most important is the cost factor since using Oracle can be very expensive, especially if all the features like Oracle Enterprise Manager or Oracle Data Guard are used. SQL Server, on the other hand, offers all advanced database engine features like Analysis Services or Reporting Services in one license cost.  The SQL Server can better handle large volumes of data processing loads.  Oracle users get locked into a single vendor with high licensing costs. However, Microsoft SQL Server offers several versions, with users having the flexibility to choose one as per the features required and pay accordingly. Among the versions are the Enterprise and the Standard models.  SQL Server keeps costs down through merging databases, visualizing servers, allotting resources optimally, and compressing data. This leads to more streamli...
Read more