Extracting refers to the action of obtaining source data from an originating source, such as a website, file archive, database or other source repository.

Overview

Extracting refers to the action of obtaining source data from an originating source; such as a website, file archive, database or other source repository. It is routinely the first step in Extract/Transform/Load operations.

Extract/Transform/Load operations (ETL)

  • Data Extraction
  • Data Transformation
  • Data Loading

Data Extract/Transform/Load operations ("ETL") describes a general procedure in computing, where data are acquired (extracted) from a source, transformed or "massaged" in any of various ways, and then saved or "loaded" into a target destination for subsequent use and retrieval.

Data extraction involves extracting data from homogeneous or heterogeneous sources; data transformation processes data by data cleaning and transforming them into a proper storage format/structure for the purposes of querying and analysis; finally, data loading describes the insertion of data into the final target destination, such as an operational data store, a data mart, relational database, data lake, or a data warehouse.

Contrast Parsing

Extracting can be distinguished from parsing, which consists of breaking the data into useful elements. Parsing can take place at any step in the ETL process, and can consist of any of various low-level operations on data, including lexical analysis, language identification, "screen scraping" and other operations.

See also