Query languages, data query languages or database query languages (DQL) are

computer language A computer language is a formal language used to communicate with a computer. Types of computer languages include: * Construction language – all forms of communication by which a human can specify an executable problem solution to a comput ...

s used to make queries in

database In computing, a database is an organized collection of data stored and accessed electronically. Small databases can be stored on a file system, while large databases are hosted on computer clusters or cloud storage. The design of databases s ...

s and information systems. A well known example is the Structured Query Language (SQL).

Types

Broadly, query languages can be classified according to whether they are database query languages or information retrieval query languages. The difference is that a database query language attempts to give factual answers to factual questions, while an information retrieval query language attempts to find documents containing information that is relevant to an area of inquiry. Other types of query languages include: * Full-text. The simplest query language is treating all terms as bag of words that are to be matched with the postings in the

inverted index In computer science, an inverted index (also referred to as a postings list, postings file, or inverted file) is a database index storing a mapping from content, such as words or numbers, to its locations in a table, or in a document or a set of d ...

and where subsequently ranking models are applied to retrieve the most relevant documents. Only tokens are defined in the CFG. Web search engines often use this approach. * Boolean. A query language that also supports the use of the Boolean operators AND, OR, NOT. * Structured. A language that supports searching within (a combination of) fields when a document is structured and has been indexed using its document structure. * Natural language. A query language that supports natural language by parsing the natural language query to a form that can be best used to retrieve relevant documents, for example with Question answering systems or conversational search.

Examples

Attempto Controlled English Attempto Controlled English (ACE) is a controlled natural language, i.e. a subset of standard English with a restricted syntax and restricted semantics described by a small set of construction and interpretation rules. It has been under developmen ...

is a query language that is also a

controlled natural language Controlled natural languages (CNLs) are subsets of natural languages that are obtained by restricting the grammar and vocabulary in order to reduce or eliminate ambiguity and complexity. Traditionally, controlled languages fall into two major types ...

. * AQL is a query language for the ArangoDB native multi-model database system. *

.QL .QL (pronounced "dot-cue-el") is an object-oriented query language used to retrieve data from relational database management systems. It is reminiscent of the standard query language SQL and the object-oriented programming language Java. .QL is ...

is a proprietary object-oriented query language for querying relational databases; successor of Datalog; * CodeQL is the analysis engine used by developers to automate security checks, and by security researchers to perform variant analysis on GitHub. *

Contextual Query Language Contextual Query Language (CQL), previously known as Common Query Language, is a formal language for representing queries to information retrieval systems such as search engines, bibliographic catalogs and museum collection information. Based on t ...

(CQL) a formal language for representing queries to information retrieval systems such as web indexes or bibliographic catalogues. * Cypher is a query language for the Neo4j graph database; * DMX is a query language for data mining models; *

Datalog Datalog is a declarative logic programming language. While it is syntactically a subset of Prolog, Datalog generally uses a bottom-up rather than top-down evaluation model. This difference yields significantly different behavior and properties ...

is a query language for

deductive database A deductive database is a database system that can make deductions (i.e. conclude additional facts) based on rules and facts stored in the (deductive) database. Datalog is the language typically used to specify facts, rules and queries in deductiv ...

s; * F-logic is a declarative object-oriented language for

s and knowledge representation. * FQL enables you to use a SQL-style interface to query the data exposed by the

Graph API The social graph is a graph that represents social relations between entities. In short, it is a model or representation of a social network, where the word graph has been taken from graph theory. The social graph has been referred to as "the ...

. It provides advanced features not available in the

. *

Gellish English Gellish is an ontology language for data storage and communication, designed and developed by Andries van Renssen since mid-1990s. It started out as an engineering modeling language ("Generic Engineering Language", giving it the name, "Gellish") bu ...

is a language that can be used for queries in Gellish English Databases, for dialogues (requests and responses) as well as for information modeling and

knowledge modeling Knowledge modeling is a process of creating a computer interpretable model of knowledge or standard specifications about a kind of process and/or about a kind of facility or product. The resulting knowledge model can only be computer interpretable ...

; *

Gremlin A gremlin is a mischievous folkloric creature invented at the beginning of the 20th century to originally explain malfunctions in aircraft and later in other machinery and processes and their operators. Depictions of these creatures vary widel ...

is an Apache Software Foundation graph traversal language for OLTP and OLAP graph systems. *

GraphQL GraphQL is an open-source data query and manipulation language for APIs, and a runtime for fulfilling queries with existing data. GraphQL was developed internally by Facebook (now Meta) in 2012 before being publicly released in 2015. On 7 No ...

is a data query language developed by

Facebook Facebook is an online social media and social networking service owned by American company Meta Platforms. Founded in 2004 by Mark Zuckerberg with fellow Harvard College students and roommates Eduardo Saverin, Andrew McCollum, Dustin Mosk ...

as an alternate to

REST Rest or REST may refer to: Relief from activity * Sleep ** Bed rest * Kneeling * Lying (position) * Sitting * Squatting position Structural support * Structural support ** Rest (cue sports) ** Armrest ** Headrest ** Footrest Arts and enter ...

and ad-hoc webservice architectures. * HTSQL is a query language that translates HTTP queries to SQL; * ISBL is a query language for

PRTV PRTV (''Peterlee Relational Test Vehicle'') was the world's first relational database management system that could handle significant data volumes. It was a relational query system with powerful query facilities, but very limited update facility a ...

, one of the earliest relational database management systems; * Jaql is a functional data processing and query language most commonly used for JSON query processing; * jq is a functional programming language often used for processing queries against one or more JSON documents, including very large ones; *

JSONiq JSONiq is a query and functional programming language that is designed to declaratively query and transform collections of hierarchical and heterogeneous data in format of JSON, XML, as well as unstructured, textual data. JSONiq is an open speci ...

is a declarative query language designed for collections of JSON documents; *

LDAP The Lightweight Directory Access Protocol (LDAP ) is an open, vendor-neutral, industry standard application protocol for accessing and maintaining distributed directory information services over an Internet Protocol (IP) network. Directory servi ...

is an application protocol for querying and modifying directory services running over TCP/IP; * LogiQL is a variant of Datalog and is the query language for the LogicBlox system. * M Formula language, a mashup query language used in Microsoft's Power Query * MQL is a cheminformatics query language for a substructure search allowing beside nominal properties also numerical properties; * MDX is a query language for

OLAP Online analytical processing, or OLAP (), is an approach to answer multi-dimensional analytical (MDA) queries swiftly in computing. OLAP is part of the broader category of business intelligence, which also encompasses relational databases, repor ...

databases; * N1QL is a

Couchbase Couchbase Server, originally known as Membase, is an open-source, distributed ( shared-nothing architecture) multi-model NoSQL document-oriented database software package optimized for interactive applications. These applications may serve many ...

's query language finding data in

Couchbase Server Couchbase Server, originally known as Membase, is an open-source, distributed ( shared-nothing architecture) multi-model NoSQL document-oriented database software package optimized for interactive applications. These applications may serve many ...

s; * Object Query Language * OCL (Object Constraint Language). Despite its name, OCL is also an object query language and an OMG standard; *

OPath WinFS (short for Windows Future Storage) was the Microsoft codenames, code name for a canceled data storage and data management, management system project based on relational databases, developed by Microsoft and first demonstrated in 2003 as an ad ...

, intended for use in querying

WinFS WinFS (short for Windows Future Storage) was the code name for a canceled data storage and management system project based on relational databases, developed by Microsoft and first demonstrated in 2003 as an advanced storage subsystem for the Micro ...

''Stores''; * Poliqarp Query Language is a special query language designed to analyze annotated text. Used in the Poliqarp search engine; *

PQL PQL, pql, or ''variation'', may refer to: * Trent Lott International Airport (FAA id: PQL), Pascagoula, Jackson County, Mississippi, US * The Porcupine's Quill, a publishing company based in Erie, Ontario, Canada * ''Project Quantum Leap'', a ficti ...

is a special-purpose programming language for managing

process model The term process model is used in various contexts. For example, in business process modeling the enterprise process model is often referred to as the ''business process model''. Overview Process models are processes of the same nature that a ...

s based on information about scenarios that these models describe; * PTQL based on relational queries over program traces, allowing programmers to write expressive, declarative queries about program behavior. * QUEL is a relational database access language, similar in most ways to SQL; * RDQL is a RDF query language; * SMARTS is the cheminformatics standard for a substructure search; *

SPARQL SPARQL (pronounced " sparkle" , a recursive acronym for SPARQL Protocol and RDF Query Language) is an RDF query language—that is, a semantic query language for databases—able to retrieve and manipulate data stored in Resource Description ...

is a query language for RDF graphs; * SQL is a well known query language and

data manipulation language A data manipulation language (DML) is a computer programming language used for adding (inserting), deleting, and modifying (updating) data in a database. A DML is often a sublanguage of a broader database language such as SQL, with the DML com ...

for relational databases; *

XQuery XQuery (XML Query) is a query and functional programming language that queries and transforms collections of structured and unstructured data, usually in the form of XML, text and with vendor-specific extensions for other data formats (JSON, b ...

is a query language for XML data sources; *

XPath XPath (XML Path Language) is an expression language designed to support the query or transformation of XML documents. It was defined by the World Wide Web Consortium (W3C) and can be used to compute values (e.g., strings, numbers, or Boolean v ...

is a declarative language for navigating XML documents; * YQL is an SQL-like query language created by Yahoo! * Search engine query languages, e.g., as used by

Google Google LLC () is an American Multinational corporation, multinational technology company focusing on Search Engine, search engine technology, online advertising, cloud computing, software, computer software, quantum computing, e-commerce, ar ...

Bing Bing most often refers to: * Bing Crosby (1903–1977), American singer * Microsoft Bing, a web search engine Bing may also refer to: Food and drink * Bing (bread), a Chinese flatbread * Bing (soft drink), a UK brand * Bing cherry, a varie ...

References

{{Authority control Computer languages Data management Programming language classification no:Database#Spørrespråk

Types

Examples

See also

References