The Object Definition Language (ODL) in object-oriented database systems is best described as what? Select the most complete characterization.

Introduction / Context:
ODL provides a formal way to declare classes, attributes, relationships, keys, and other schema-level constructs for object-oriented databases. It plays the same role for OODBs that SQL DDL plays for relational systems.

Given Data / Assumptions:

• We are discussing schema design, not ad-hoc queries.
• ODL captures logical structure of persistent objects.
• Implementations use ODL to realize logical schemas in the database.

Concept / Approach:

ODL is simultaneously a data definition language and a means to develop and implement logical schemas. It defines types and relationships that the ODBMS enforces, enabling storage, navigation, and integrity consistent with object modeling.

Step-by-Step Solution:

Verification / Alternative check:

Documentation positions ODL as the schema language; tools often generate storage structures from ODL definitions.

Why Other Options Are Wrong:

Each single statement is true but incomplete; “All of the above” is the most complete description.

Common Pitfalls:

Assuming ODL also specifies behavior/method bodies; ODL focuses on structure and constraints.

Final Answer:

All of the above.