Читать книгу Official Google Cloud Certified Professional Data Engineer Study Guide - Dan Sullivan - Страница 45

Structured and semi-structured data has a schema associated with it. Structured data is usually stored in relational databases whereas semi-structured data is often stored in NoSQL databases. The schema influences how data is stored and accessed, so once you have determined which kind of storage technology to use, you may then need to design a schema that will support optimal storage and retrieval.

The distinction between relational and NoSQL databases is becoming less pronounced as each type adopts features of the other. Some relational databases support storing and querying JavaScript Object Notation (JSON) structures, similar to the way that document databases do. Similarly, some NoSQL databases now support ACID (atomicity, consistency, isolation, durability) transactions, which are a staple feature of relational databases.