Practice exercise

• Which two statements are true about associative arrays?

  1. Associative arrays can have negative subscripts.

  2. Associative arrays are always dense collections.

  3. Associative arrays don't need initialization in a PL/SQL block.

  4. The upper limit of associative arrays can by dynamically modified.

• Which of the following statements is true about nested tables?

  1. Nested tables are stored in a segment different from that of a parent table.

  2. Nested table columns can have string subscripts.

  3. Nested tables can grow dynamically up to any extent.

  4. A database column of nested table collection type can be separately queried by its storage name.

• Only varrays can have sequential numbers as subscripts.

  1. True

  2. False

• Which of the following associative array declarations is/are correct:

  DECLARE
  TYPE T1 IS TABLE OF NUMBER INDEX BY BOOLEAN;
  TYPE T2 IS TABLE OF VARCHAR2(10) INDEX BY NUMBER;
  TYPE T3 IS TABLE OF DATE INDEX BY SIGNTYPE;
  TYPE T4 IS TABLE OF EMPLOYEES%ROWTYPE INDEX BY POSITIVE;
  BEGIN
  …
  …
  END;

  1. T1

  2. T2

  3. T3

  4. T4

• Which of the...