"Structured data — typically categorized as quantitative data — is highly organized and easily decipherable by machine learning algorithms. Developed by IBM in 1974, structured query language (SQL) is the programming language used to manage structured data. By using a relational (SQL) database, business users can quickly input, search and manipulate structured data."
Source: IBM (2021). Structured vs. Unstructured Data: What`s the Difference? IBM Cloud Education.
Online: https://www.ibm.com/cloud/blog/structured-vs-unstructured-data