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A '''database search engine''' is a [[search engine]] that operates on material stored in a digital [[database]].
{{copyedit|date=June 2015}}
Categories of [[search engine]] software include: Web search or full-text search (i.e. [[Lucene]]), database or structured data search such as [[Diesel point]], and mixed or [[enterprise search]] like [[Google Search Appliance]]. The largest web internet directories, such as [[Google]] and [[Yahoo!]], utilize hundreds of thousands of computers to process billions of web pages, returning results for thousands of searches per second. High volumes of queries and text processing require the software to run in a highly distributed environment with a high degree of redundancy.
== Search engines ==
=== Modern search engine components: ===
Categories of search engine software include:
Searching for text-based content in [[databases]] or [[structured data]] formats (such as [[XML]], [[Comma-separated values|CSV]], etc.) presents special challenges and opportunities, which a number of specialized search engines resolve. Databases are slow when solving complex queries, which have multiple logical or [[string matching]] arguments. Databases allow logical queries - for instance, the use of multi-field [[boolean logic]] - which full-text searches don't. "Crawling" (a human by-eye search) is not necessary to find information stored in a database, since the data is already structured, although it is often necessary to index the data in a more compact form that is designed to allow for faster searches. ▼* Web search or full-text search (e.g. [[Lucene]]).
* [[Database]] or [[structured data]] search (e.g. [[Dieselpoint]]).
* Mixed or [[enterprise search]] (e.g. [[Google Search Appliance]]).
The largest online directories, such as [[Google]] and [[Yahoo]], utilize thousands of computers to process billions of website documents using [[web crawlers]] or [[spiders (software)]], returning results for thousands of searches per second. Processing high query volumes requires software to run in a distributed environment with redundancy.
Database search engines were initially (and still usually are) included with major database software products. As such, they are usually called "indexing engines". However, these indexing engines are relatively limited in their ability to customize indexing formats (such as compounding, normalization, transformation, [[transliteration]], etc.). Usually, they do not provide sophisticated data matching technology (such as [[string matching]], [[boolean logic]], algorithmic methods, search scripting, etc.).
== Components ==
In more advanced database search systems, relational databases are indexed by compounding multiple tables into a single table containing only the fields that need to be "queried" (displayed in search results). The actual data-matching engines can include any functions, such as basic string matching, normalization, and transformation. Database search technology is heavily used by many large entities, such as government database services, e-commerce companies, web advertising platforms, telecommunications service providers, etc.
▲Searching for text-basedtextual content in [[databases]] or [[structured data]] formats (such as [[XML]] , and [[Comma-separated values|CSV]] , etc.) presents special challenges and opportunities , which a number of specialized search engines resolve. Databases are slow when solving complex queries, which have multiple logical or [[ string matchingDatabases]] arguments. Databases allow logical queries -such for instance,as the use of multi-field [[ booleanBoolean logic]] , - whichwhile full-text searches don'tdo not. "Crawling" (a human by-eye search) is not necessary to find information stored in a database , sincebecause the data is already structured ,. although[[index it is often necessary to index(database)|Indexing]] the data in a more compact form that is designed to allowallows for faster searches.
Database search engines are usually included with major database software products.
== Applications ==
Database search technology is used by large public and private entities including government database services, e-commerce companies, online advertising platforms, telecommunications service providers and other consumers with a need to access information in large repositories.
==See also==
*[[Outline of search engines]]
*[[Search engine]]
*[[WebList crawlerof search engines]]
*[[Search engine indexing]]
*[[Enterprise search]]
==External links==
* [http://www.searchtools.com/info/database-search.html Searching for Text Information in Databases]
{{DEFAULTSORT: Search Engine Technology}}
[[Category:Information retrieval systems]]
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