QUEL is a relational database query language , based on tuple relational calculus , with some similarities to SQL . It was created as a part of the Ingres DBMS effort at University of California, Berkeley , based on Codd 's earlier suggested but not implemented Data Sub-Language ALPHA . QUEL was used for a short time in most products based on the freely available Ingres source code, most notably in an implementation called POSTQUEL supported by POSTGRES . As Oracle and DB2 gained market share in the early 1980s, most companies then supporting QUEL moved to SQL instead. QUEL continues to be available as a part of the Ingres DBMS, although no QUEL-specific language enhancements have been added for many years.
6-563: (Redirected from QUEL ) [REDACTED] Look up quel in Wiktionary, the free dictionary. Quel may refer to: QUEL query languages , a relational database access language Quel, La Rioja , a municipality in La Rioja, Spain Quél , taxonomic author abbreviation for Lucien Quélet (1832–1899), French naturalist and mycologist Topics referred to by
12-543: A delimiter, as opposed to a data type. Changing the into to a from reverses the process. Similar commands are available in many SQL systems, but usually as external tools, as opposed to being internal to the SQL language. This makes them unavailable to stored procedures . QUEL has an extremely powerful aggregation capability. Aggregates can be nested, and different aggregates can have independent by-lists and/or restriction clauses. For example: This example illustrates one of
18-434: Is a sample of a simple session that creates a table, inserts a row into it, and then retrieves and modifies the data inside it and finally deletes the row that was added (assuming that name is a unique field). Another feature of QUEL was a built-in system for moving records en-masse into and out of the system. Consider this command: which creates a comma-delimited file of all the records in the student table. The d1 indicates
24-499: Is different from Wikidata All article disambiguation pages All disambiguation pages QUEL query languages QUEL statements are always defined by tuple variables , which can be used to limit queries or return result sets. Consider this example, taken from one of the first original Ingres papers: Here E is a tuple variable that ranges over the EMPLOYEE relation, and all tuples in that relation are found which satisfy
30-571: The qualification `E.Name = "Jones"`. The result of the query is a new relation W, which has a single domain COMP that has been calculated for each qualifying tuple. Additional queries can then be made against the relation W. An equivalent SQL statement is: In this example, the relation is being stored in a new table W. This is not a direct analog of the QUEL version; relations in QUEL are more similar to temporary tables seen in most modern SQL implementations. Here
36-405: The same term [REDACTED] This disambiguation page lists articles associated with the title Quel . If an internal link led you here, you may wish to change the link to point directly to the intended article. Retrieved from " https://en.wikipedia.org/w/index.php?title=Quel&oldid=1084131773 " Category : Disambiguation pages Hidden categories: Short description
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