Database search engine: Difference between revisions

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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 webpages, and returnreturning 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.

=== Modern search engines have the following mainengine components: ===

Searching for text-based content in [[databases]] or other [[structured data]] formats ([[XML]], [[Comma-separated values|CSV]], etc.) presents some special challenges and opportunities, which a number of specialized search engines resolve. Databases are slow when solving complex queries, (withwhich have multiple logical or [[string matching]] arguments. Databases allow logical queries, which full-text search doesn't (use of multi-field boolean logic for instance). There is no crawling necessary for a database, since the data is already structured,. butAlthough it is often necessary to index the data in a more compact form, designed to allow for faster search.

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 (compounding, normalization, transformation, [[transliteration]], etc.) . Usually they do not provide sophisticated data matching technology ([[string matching]], [[boolean logic]], algorithmic methods, search scripting, etc.).

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 (or displayed in search results). The actual data matching engines can include any functions from basic string matching, normalization, and transformation. Database search technology is heavily used by government database services, e-commerce companies, web advertising platforms, telecommunications service providers, etc.

==See also==