n The Object Definition Language (ODL) is a language for defining the specifications of object types for
ODMG-compliant systems, equivalent to the Data Definition Language (DDL) of traditional DBMSs. The
ODL defines the attributes and relationships of types and specifies the signature of the operations, but it does
not address the implementation of signatures.
n The Object Query Language (OQL) provides declarative access to the object database using an SQL-like
syntax. It does not provide explicit update operators, but leaves this to the operations defined on object types.
An OQL query is a function that delivers an object whose type may be inferred from the operator contributing
to the query expression. OQL can be used for both associative and navigational access.