Elasticsearch field types¶

In Elasticsearch, data is stored as JSON-like documents, analogous to rows in a relational database, while fields correspond to columns.^[600-developer__Elasticsearch.md] The definition of these fields and their types is referred to as the Mapping^[600-developer__Elasticsearch.md].

Field types determine how data is indexed and queried. The two primary types discussed in the context of basic search configurations are keyword and text^[600-developer__Elasticsearch.md].

Common Field Types¶

`text`¶

The text type is designed for full-text search.^[600-developer__Elasticsearch.md] * Analysis: Fields of this type are analyzed, meaning the text is broken down into tokens (a process called tokenization) by an analyzer. * Inverted Index: These tokens are stored in an inverted index^[600-developer__Elasticsearch.md]. * Use Case: Ideal for searching within long content, such as the body of an email or a product description, where finding matches for parts of the text is required.

`keyword`¶

The keyword type is used for exact value matching.^[600-developer__Elasticsearch.md] * No Analysis: Unlike text, keyword fields are not analyzed or split into tokens.^[600-developer__Elasticsearch.md] * Matching: They are used for filtering, sorting, and aggregations. Queries against keyword fields typically treat the entire string as a single entity. * Use Case: Suitable for fields like IDs, email addresses, tags, or status codes where the exact value must match.

Search Behavior and Queries¶

The field type dictates which query types are effective.^[600-developer__Elasticsearch.md]

match query: Typically used on text fields. It analyzes the input search string and breaks it down to match against the indexed tokens.
term query: Typically used on keyword fields or for exact lookups. It searches for the exact, un-analyzed term in the inverted index^[600-developer__Elasticsearch.md]. For example, searching for "iPhone 手機" using a term query would look for that exact phrase rather than the individual words "iPhone" or "手機"^[600-developer__Elasticsearch.md].

Mapping Configuration¶

Mappings can be defined manually or configured to be dynamic^[600-developer__Elasticsearch.md].

Sources¶

600-developer__Elasticsearch.md