Chapter 2: Managing Mappings
Mapping is a primary concept in Elasticsearch that defines how the search engine should process a document and its fields to be effectively used in search and aggregations.
Search engines perform the following two main operations:
- Indexing: This action is used to receive a document, process it, and store it in an index.
- Searching: This action is used to retrieve the data from the index based on a query.
These two operations are strictly connected; an error in the indexing step leads to unwanted or missing search results.
Elasticsearch, by default, has explicit mapping at the index level. When indexing, if a mapping is not provided, a default one is created and guesses the structure from the JSON data fields that the document is composed of. This new mapping is then automatically propagated to all the cluster nodes: it will begin part of the cluster's state.
The default type mapping has sensible default values, but when you want to change their behavior or customize several other aspects of indexing (object to special fields, storing, ignoring, completion, and so on), you need to provide a new mapping definition.
In this chapter, we'll look at all the possible mapping field types that document mappings are composed of.
In this chapter, we will cover the following recipes:
- Using explicit mapping creation
- Mapping base types
- Mapping arrays
- Mapping an object
- Mapping a document
- Using dynamic templates in document mapping
- Managing nested objects
- Managing a child document with a join field
- Adding a field with multiple mappings
- Mapping a GeoPoint field
- Mapping a GeoShape field
- Mapping an IP field
- Mapping an Alias field
- Mapping a Percolator field
- Mapping the Rank Feature and Feature Vector fields
- Mapping the Search as you type field
- Using the Range Field type
- Using the Flattened field type
- Using the Point and Shape field types
- Using the Dense Vector field type
- Using the Histogram field type
- Adding metadata to a mapping
- Specifying different analyzers
- Using index components and templates
