Each field type is treated differently by the search engine to decide if it needs to store the
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actual data or just use it for creating the index file. Table 8.1 shows the key field types and what the differences
are.
Table 8.1 Lucene field types for adding fields to an index
Name Indexed Stored Tokenised Notes
Keyword Yes Yes No Use for storing and indexing data that is already split into separate
words for searching.
UnIndexed No Yes No Use for data that isn??™t searched on, but is displayed in the search
results, such as dates or database id fields.
Text Yes Yes Yes Use for storing data that is both indexed and used in the search results
display. This data is split into separate words for indexing.
Unstored Yes No Yes Use for indexing the main content of the document. The actual data isn??™t
stored as you won??™t be using it for search results display.
Binary No Yes No Use for storing binary data that is associated with the document, such
as a thumbnail.
There are two reasons for adding a field to the search index: providing the search data and providing for
display of the results.
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