What is the difference between structured data and unstructured data?

Simply put in words, structured data is the data that can easily be stored in relational databases. For example numeric values or other objective values. As the name suggests it has structure to it.

Unstructured data on the other hand, is more generic. It could be in the form of text, documents, audio, video and non-organized sorts. For example, the data from the comments section of various social networking sites would be classified as unstructured data.

Structured Data

Some business experts estimate that about twenty percent of all data used in business decisions is structured data. Structured data is easily organized and generally stored in databases. Structured data generally consists of numerical information and is objective. It simply is data that exists - there is no interpretation.

Some types of structured data can be machine generated, such as data that comes from medical devices (heart rate, blood pressure), manufacturing sensors (rotation per minute, temperature), or web server logs (number of times a page is visited). Structured data can also be human generated - data such as age, zip code, and gender.

If we think about the structured data a web server log might keep, we could find out how many customer inquiries there have been, how long it took to solve a problem, and how the customer rated his experience.

Unstructured Data

Unstructured data may represent approximately 80% of the information that is used to make good business decisions. Unstructured data is more subjective and is usually text heavy. It can't generally be put into a data structure, like columns or rows. Unstructured data can be found in documents, presentations, audio, images, videos messages and books

Structured data is easily searchable by basic algorithms. Examples include spreadsheets and data from machine sensors. Unstructured data is more like human language. It doesn't fit nicely into relational databases like SQL, and searching it based on the old algorithms ranges from difficult to completely impossible.