In which scenario would index be most useful?

Question

Options

• AThe indexed column is declared as NOT NULL.
• BThe indexed columns are used in the FROM clause.
• CThe indexed columns are part of an expression.
• DThe indexed column contains a wide range of values.

• A
  15% (6)
• B
  7% (3)
• C
  5% (2)
• D
  73% (30)

Explanation

Index will be useful if the indexed column contains a wide range of values. Especially B- tree indexes will work better for tables with a wide range of values. But for tables just with some distinct values bitmap indexes will be more helpful. Incorrect Answers A: Oracle automatically creates index for NOT NULL columns, so you don't need create an index B: There are only table names in the FROM clause, not columns. C: Index may be will not work if the indexed columns are part of an expression. You need to avoid expressions if you want to use index.

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