Oracle 26ai Object Types and SQL Collections - Quiz

Each question is worth one point, for 5 points total. Select one answer per question. Unanswered or invalid responses receive no credit.

1. Which statement distinguishes an Oracle SQL object type from an object instance? Select the one best answer.
	A. They are interchangeable names for the same stored row.
	B. A type contains customer data, while an instance contains only a definition.
	C. The type defines attributes and optional methods; an instance supplies values for that structure.
	D. Every instance is persistent, while type definitions cannot be stored in a schema.

2. Which statement correctly describes what Oracle object-relational features add to a design? Select the one best answer.
	A. They make every object attribute private and force all writes through methods.
	B. They remove the need for relational keys, constraints and SQL.
	C. They are required because relational tables cannot model customers with related child rows.
	D. They offer reusable typed structures and associated operations; integrity and lifecycle rules still need explicit design.

3. Which collection types can be created as schema-level SQL types for collection-valued table columns in Oracle 26ai? Select the one best answer.
	A. Associative arrays only.
	B. VARRAYs and nested tables.
	C. Object tables and scalar columns.
	D. Every PL/SQL collection, including string-indexed associative arrays.

4. SALE_HEADER has a nested-table column named DETAIL_NEST. Which query returns each collection element as a separate row? Select the one best answer.
	A. SELECT d.* FROM sale_header s, TABLE(s.detail_nest) d;
	B. SELECT s.detail_nest FROM sale_header s;
	C. SELECT d.* FROM sale_header s, REF(s.detail_nest) d;
	D. SELECT d.* FROM sale_header s, VARRAY(s.detail_nest) d;

5. An initialized PL/SQL nested table becomes sparse after individual elements are deleted. Which approach visits its remaining elements safely? Select the one best answer.
	A. Loop from 1 through COUNT and access every index without checking whether it exists.
	B. Call EXTEND before each read to restore every deleted element automatically.
	C. Assume that every nested table remains dense after DELETE.
	D. Start with FIRST, process that element, and advance with NEXT until the index is NULL.

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