Searching a for a text-based content in [[databases]] or [[structured data]] formats (such as [[XML]] and [[Comma-separated values|CSV]]) presents special challenges and opportunities which specialized search engines resolve. [[Databases]] are slow when solving complex queries which have multiple logical or [[string matching]] arguments. However, databases allow logical queries such as the use of multi-field [[Boolean logic]], while full-text searches do not. "Crawling" (a human by-eye search) is not necessary to find information stored in a database because the data is already structured, though it is often necessary to index the data in a more compact form to allow for faster searches.
Database search engines are usually included with major database software products. As such, they are commonly called "indexing engines." However, these indexing engines are relatively limited in their ability to customize indexing formats (such as compounding, normalization, transformation and [[translation]]). Usually, these search engines do not provide sophisticated data-matching technology (such as [[string matching]], [[Boolean logic]], algorithmic methods and search scripting).
