Final answer:
ODL supports the definition of class structures, attributes, methods, and relationships between objects in object-oriented databases.
Step-by-step explanation:
The Object Definition Language (ODL) is used for defining the data types and relationship structures that exist in a database managed by an object-oriented database management system (OODBMS). ODL is akin to a blueprint that dictates how data is stored, retrieved, and managed within the system. It also aids in specifying keys for object identification and index creation for performance enhancements.
ODL supports the creation of class definitions that describe the structure and behaviors of objects in the database. These definitions include specifying attributes, which are the properties or data associated with an object, as well as methods, operations that can be performed on the objects. ODL also allows for the specification of relationships between classes, such as inheritance (where a class shares the structure or behavior of another class) and association (a general relationship between instances of classes).
Moreover, ODL provides mechanisms for specifying keys for object identification and for creating indices that improve querying performance. Overall, ODL supports the critical features needed to define the complex structures and relationships inherent in object-oriented databases.