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The fields property is very useful in data processing because it allows you to define several ways to process a field data.

For example, if we are working on documental content (such as articles, word documents, and so on), we can define fields as subfield analyzers to extract names, places, date/time, geo location, and so on.

The subfields of a multifield are standard core type fields—we can do every process we want on them, such as search, filter, aggregation, and scripting.