Linking data physically: are the two basic constructs for connecting data items sequential placement and pointer-based references?
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AValid — sequential storage and pointers are fundamental linking constructs
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BInvalid — only pointers are used in databases
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CValid only when using heap files
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DApplies solely to hierarchical databases
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EValid only if pages are 8 KB
Answer
Correct Answer: Valid — sequential storage and pointers are fundamental linking constructs
Explanation
Introduction / Context:Physical data access relies on how records are arranged and connected. Two foundational mechanisms are sequential organization and pointer-based linking.
Given Data / Assumptions:
- Sequential placement (clustering) keeps related records near each other to enable efficient scans.
- Pointers (record IDs, page/slot references, B-Tree child pointers) allow direct navigation between related items.
- Many structures combine both ideas (for example, clustered B-Trees with leaf-level sibling pointers).
Concept / Approach:Sequential storage exploits spatial locality; pointers enable selective traversal. Together, they underpin heaps, clustered indexes, linked lists, and tree structures.
Step-by-Step Solution:Identify sequential clustering benefits for range queries.Identify pointer-based navigation for joins and index traversals.Recognize coexistence in common index designs.Therefore, the statement is valid.
Verification / Alternative check:Index diagrams show sibling and child pointers; storage guides emphasize clustering for scan workloads.
Why Other Options Are Wrong:Limiting to pointers alone ignores sequential organizations; tying validity to heaps, hierarchy, or page size is unjustified.
Common Pitfalls:Overlooking fragmentation that breaks sequential locality; ignoring pointer maintenance costs on updates.
Final Answer:Valid — sequential storage and pointers are fundamental linking constructs