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

Info icon This preview shows page 53. Sign up to view the full content.

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
Image of page 53
This is the end of the preview. Sign up to access the rest of the document.
  • Winter '16
  • zeenath
  • Relational Database, ........., Entity-relationship model, Relational model

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern