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Types of Data Extraction

Data extraction is an important process that is used to collect data from different databases for onward processing and interpretation. As a result, almost all fields require data extraction as a tool for data mining to make critical business and operational decisions.

Data extraction is also the first step in ETL (extract, transform, and load). Without data extraction, many activities will not be conducted.

Types of Data Extraction Techniques

The extraction of data is essential for the data engineer. The data extraction specialists are required to make important decisions about data extraction processes. These decisions are:

  • Data extraction methods
  • Data cleaning and transformation processes

However, this article is going to focus only on data extraction methods.

Data Extraction Methods

In general, there are two main data extraction methods, which are Physical and Logical.

Physical Extraction

This best works for source systems with limitations. Older storage systems can be difficult or even impossible to extract using logical extraction. Therefore, physical extraction must be used. Such type of physical extraction can only be carried out using Online and Offline Extraction methods.

The physical online extraction of data is usually done directly from a warehouse of data. As such, extraction tools must be in direct physical contact with the source or other forms of transitional systems. In this case, a transitional system refers to an exact replica of the source system but with a better structure.

Offline extraction

For an offline extraction, data collection occurs from outside the source. As a result, direct extraction does not occur from the system source. For offline data extraction, data is mostly structured. The extraction process for the offline data extraction scheme is influenced by the range of data to be collected. It also influences the phase of the ETL process.

Logical Extraction

Logical Extraction – works for different types of systems including cloud-based schemes. Logical extraction also involves two options, which are full extraction and incremental extraction.

In terms of full extraction, data collection is basically done directly from the main system source of data. It is carried out all at once without any breakage. As a result, no form of extra logical information is required for the process to be completed. Therefore, the full extraction method does not require the information about source system updates.

In addition, the full extraction method does not allow for data collection of specific data points. Rather the entire data collection must be extracted even if only a piece of data is needed.

Incremental extraction

The incremental extraction, on the other hand, is different from the full extraction method. In this case, the data extraction method is done with respect to change in the data structure. The incremental extraction method is intelligent enough to understand the change in the database with respect to time. Therefore, when data extraction is used to collect data, only the required piece of data point is collected from the database.

However, data extraction experts must deploy complex logical extraction tools to collect data using incremental extraction techniques. Nonetheless, this type of data extraction process is more efficient.

Data Capture

Data capture is a cutting-edge extraction methodology. It allows the extraction of data from records, altering it into readable data. This method is utilized to gather critical organizational data when the original designs are in the shape of paper/electronic records.

The data capture techniques include the service of optical character recognition tools. Data is first transformed into machine-readable data. The important point to note here is that automated data capture methods play a significant role in merging standard businesses into the fold. These techniques decrease the requirement for complicated work, such as manual data entry. The methods are more immediate and more cost-efficient. With the use of Data Capture, companies can now efficiently upload their administrative data into smart techniques. Contemporary data capture tools can now even build analytical maps so that users can pick their extraction technique.

Examples of Data Extraction

Big Data

Consider the biggest pizza establishment in the world, and one cause for that is the organization’s capacity to accept orders via a wide spectrum of technologies, such as smartphones and even social media. All of these tracks induce massive pieces of data, which the company ought to incorporate to have an understanding of its international processes and clients’ choices. This Pizza company can use one of the mentioned data extraction techniques to gather valuable information.


More than 20,000 students enroll in one University each year. That signifies the academy develops huge data streams across its diverse branches, units, and assignments. To fetch all that data into one stream, the university can keep an open-source design and a complete data administration forum to extract and handle data from each head of the source. The outcome is a scalable solution that permits the university to orchestrate more of its help toward researchers and spend less time and funds observing its data integration technique.


The inclusion of cloud storage has had a substantial effect on how companies and institutions handle their data. The cloud has created the ETL operation more efficient and adaptable than ever before, in addition to improvements in data security, warehouse, and processing. Without having to preserve their own servers or data designs, companies can now use data from any location and manage it in real-time. More companies are starting to move data away from conventional on-site procedures by employing hybrid and cloud-native data alternatives.

For example, the data topography is correspondingly being changed by the Internet of Things (IoT). Medical devices are increasingly generating data in addition to mobile phones and laptops. Once the data has been obtained and transformed, the development is an ever-increasing magnitude of data that may be used to push a firm’s competitive edge.

The trigger is the most straightforward incremental data extraction process. If authorized, then it can be utilized to alter source tables and create triggers. In many circumstances where source tables have various users or administrators, then they won’t be capable of altering the table though. But a single owner can execute triggers to perform with design, updates, or omissions of records. With triggers, users generally require a ‘change table’ where primary keys or modified logs are kept so they can incrementally pack only these logs.

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