If the search key is a candidate key we add the word

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If the search key is a candidate key, we add the word unique to the definition. In that case, head2right If the search-key is not a candidate key, an error message will appear. head2right If the index creation succeeds, any attempt to insert a tuple violating this requirement will fail. head2right The unique keyword is redundant if primary keys have been defined with integrity constraints already. For example, to define an index on branch-name for the branch relation: create index b-index on branch(branch-name) Removing an Index drop index index-name
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