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{{Short description|Query language for object-oriented databases}}
{{Multiple issues|
{{unreferenced|date=June 2012}}
{{Sources exist|date=July 2022}}
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'''Object Query Language''' ('''OQL''') is a [[query language]] standard for [[object database|object-oriented databases]] modeled after [[SQL]] and developed by the [[Object Data Management Group]] (ODMG). Because of its overall complexity, the complete OQL standard has not yet been fully implemented in any software. The OQL standard influenced the design of later query languages such as [[JDOQL]] and [[EJB QL]], though none are considered to be any version of OQL.

==General rules==
The following rules apply to OQL statements:
* All complete statements must be terminated by a semicolon.
* A list of entries in OQL is usually separated by commas but not terminated by a comma (,).
* Strings of text are enclosed by matching quotation marks.

==Examples==
===Simple query===
The following example illustrates how one might retrieve the [[CPU]] speed of all PCs with more than 64MB of [[random-access memory|RAM]] from a fictional [[Personal computer|PC]] database:

<syntaxhighlight lang="sql">
SELECT pc.cpuspeed
FROM PCs pc
WHERE pc.ram > 64;
</syntaxhighlight>

===Query with grouping and aggregation===
The following example illustrates how one might retrieve the average amount of [[random-access memory|RAM]] on a [[Personal computer|PC]], grouped by manufacturer:

<syntaxhighlight lang="sql">
SELECT manufacturer, AVG(SELECT part.pc.ram FROM partition part)
FROM PCs pc
GROUP BY manufacturer: pc.manufacturer;
</syntaxhighlight>

Note the use of the keyword <code>partition</code>, as opposed to aggregation in traditional SQL.

==See also==
* [[Object Data Management Group]] (ODMG)
* Object Definition Language

==References==
{{reflist}}

{{Query languages}}

[[Category:Query languages]]


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