The Object Definition Language (ODL) in object-oriented database systems is best described as what? Select the most complete characterization.
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AUsed to develop logical schemas
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BA data definition language for OODB
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CA method to implement a logical schema
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DAll of the above.
Answer
Correct Answer: All of the above.
Explanation
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:
Recognize ODL as DDL for OODBs.Acknowledge its role in logical schema design.Accept that actual schema implementation proceeds from the ODL declarations.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.