Learn in the textbookDatabase and DBMS Basics, and Types of NoSQL
DefinitionA document-oriented database (ドキュメント指向データベース) is a NoSQL type that saves each document that has fields, such as JSON or XML, as one record.
ExplanationEach document may carry different fields, so there is no need to align columns as in a table. Because the DBMS can read the fields inside a document, you can also search using a field's value as the condition.
AnalogyRather than a fixed application form, it is like a binder of free-form cards, each with different boxes filled in depending on the person.
Memory hookA document is a piece of paperwork: one sheet is one record, just as it is.