The ObjectQuery Language (OQL) is an object-oriented query language for object-oriented data structures proposed by the Object Database Management Group
(ODMG). OQL can be used to populate object-oriented data structures, such as those in the Object Definition Language
(ODL), with values and read them. OQL uses essentially the same commands as the Structured Query Language (SQL) query language for relational databases. The syntax of the object query language OQL is extended compared to SQL by additional features for complex objects, inheritance and relationships.