Learn in the textbookClassifying Data by Attribute and Structure
DefinitionStructured data (構造化データ) is data organized into a table of rows and columns according to fields (columns) decided in advance.
ExplanationTypical examples are tables in a relational database and a sales list in a spreadsheet. Because each value belongs to a known field, a computer can search by condition and total or sort by field without any extra preparation.
AnalogyLike an application form with printed boxes. Names go in the name box and dates in the date box, so even hundreds of forms can be tallied the same way.