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==Index data structures==
;Text/Attribute Index
:Both the text and attribute index are based on a balanced B-Tree and support exact matches and range queries.
;Full-Text Index (Standard)
:The standard full-text index is implemented as sorted array structure. It is optimized for simple and fuzzy searches.
;Full-Text Index (Wildcards enabled)
:A second full-text index is implemented as a compressed trie. It needs slightly more memory than the standard full-text index, but it supports more features, such as full wildcard search.
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; Text Index
: This index speeds up equality tests and simple range queries on text nodes in XPath location steps with predicates.
; Attribute Index
: This index speeds up equality tests and simple range queries on attribute value in XPath location steps with predicates.
; [[Full-Text Index: [[|Full-TextIndex]] indexes : This index speeds up queries using the {{Mono|contains text}} keyword. Internally, BaseX handles two different index structures: the default index sorts all keys alphabetically by their character length. It is particularly fast if fuzzy searches are very powerful structuresperformed. The second index is a compressed trie structure, which are mainly used in information retrieval use casesneeds slightly more memory, but is specialized on wildcard searches.
With {{Mark|Version 7.1}}, a new database option was introduced to support [[Options_(Snapshot)#UPDINDEX|incremental indexing]] of texts and attributes.
==Example Queries==
The following queries are examples for expressions that will be optimized for index access (provided that the relevant index exists in a particular database):
===Name/Path Index===
* <code>//node[text() contains text 'Usebiliti' using fuzzy]</code>
* <code>//book[chapter contains text ('web' ftor 'WWW' using no stemming) ftand 'diversity' using stemming distance at most 5 words]</code>
[[Category:Internals]] [[Category:XQuery]]
