Learn in the textbookClassifying Data by Attribute and Structure
DefinitionUnstructured data (非構造化データ) is text, images, audio, video, and other data that do not fit into fixed fields.
ExplanationExamples include email body text, SNS posts, security camera footage, and recorded phone calls. It cannot be searched or totaled like a table as it stands, so features are first extracted, for instance by picking out words from text or by image recognition, before the data is analyzed.
AnalogyLike the free-comment box on a survey. Each person writes something different at a different length, so you cannot count anything until you read it and pull out the content.