Query LanguageA query language provides an interface to a database by offering a format for inputting search terms. One such language is SQL, (structured query language) developed at IBM and in wide use in database management systems.
The query language specifies the query string, or the particular parameters passed on to a Web search engine. Some query languages accept natural language queries, expressed using the grammar of normal conversation. Other query languages use Boolean queries, based on Boolean logic operators. Natural query languages are more convenient, but not as focused and precise as Boolean queries.