Key concepts

In the previous section, we learned some core concepts such as clusters, nodes, shards, replicas, and so on. We will briefly introduce the other key concepts in this section. Then, we'll drill down into the details in subsequent chapters.

Mapping concepts across SQL and Elasticsearch

In the early stages of Elasticsearch, mapping types were a way to divide the documents into different logical groups in the same index. This meant that the index could have any number of types. In the past, talking about index in Elasticsearch is similar to talking about database in SQL. In addition, the discussion of viewing index type in Elasticsearch is equivalent to a table in SQL is also very popular. According to the official...