{"id":189842,"date":"2025-02-10T14:38:02","date_gmt":"2025-02-10T14:38:02","guid":{"rendered":"https:\/\/learnexams.com\/blog\/?p=189842"},"modified":"2025-02-10T14:38:05","modified_gmt":"2025-02-10T14:38:05","slug":"describe-the-concept-of-transitive-dependency-and-describe-how-this-concept-relates-to-3nf","status":"publish","type":"post","link":"https:\/\/www.learnexams.com\/blog\/2025\/02\/10\/describe-the-concept-of-transitive-dependency-and-describe-how-this-concept-relates-to-3nf\/","title":{"rendered":"Describe the concept of transitive dependency and describe how this concept relates to 3NF"},"content":{"rendered":"\n
    \n
  1. Describe the concept of transitive dependency and describe how this concept relates to 3NF. Provide an example to illustrate your answer.<\/li>\n\n\n\n
  2. Discuss how the definitions of 2NF and 3NF based on primary keys differ from the general definitions of 2NF and 3NF. Provide an example to illustrate your answer.<\/li>\n<\/ol>\n\n\n\n

    The Correct Answer and Explanation is :<\/strong><\/mark><\/p>\n\n\n\n

    1. Transitive Dependency and Its Relation to 3NF<\/h3>\n\n\n\n

    Transitive Dependency<\/strong> occurs when one non-prime attribute (a column not part of any candidate key) depends on another non-prime attribute through a third non-prime attribute. In other words, a transitive dependency happens when an attribute indirectly depends on the primary key via another attribute.<\/p>\n\n\n\n

    Example<\/strong>:
    Consider a table containing the following columns: StudentID<\/code>, StudentName<\/code>, StudentCity<\/code>, and CityZipCode<\/code>. The StudentID<\/code> is the primary key, and the CityZipCode<\/code> depends on the StudentCity<\/code>, which in turn depends on StudentID<\/code>. So, the relationship between StudentCity<\/code> and CityZipCode<\/code> is a transitive dependency.<\/p>\n\n\n\n

    StudentID<\/th>StudentName<\/th>StudentCity<\/th>CityZipCode<\/th><\/tr><\/thead>
    1<\/td>Alice<\/td>New York<\/td>10001<\/td><\/tr>
    2<\/td>Bob<\/td>Los Angeles<\/td>90001<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n

    Here, CityZipCode<\/code> depends on StudentCity<\/code>, and StudentCity<\/code> depends on StudentID<\/code>. So, CityZipCode<\/code> depends transitively on StudentID<\/code> through StudentCity<\/code>.<\/p>\n\n\n\n

    3NF and Transitive Dependency<\/strong>:
    Third Normal Form (3NF) requires that a table be in Second Normal Form (2NF) and that no transitive dependency exists<\/strong> between non-prime attributes and the primary key. In other words, every non-prime attribute must directly depend on the primary key, not through another non-prime attribute.<\/p>\n\n\n\n

    To bring the above table into 3NF, we would split it into two tables: one for students and another for cities.<\/p>\n\n\n\n

    Corrected tables:<\/h4>\n\n\n\n
      \n
    1. Student<\/code> (StudentID, StudentName, StudentCity)<\/li>\n\n\n\n
    2. City<\/code> (StudentCity, CityZipCode)<\/li>\n<\/ol>\n\n\n\n

      2. Definitions of 2NF and 3NF Based on Primary Keys<\/h3>\n\n\n\n

      2NF (Second Normal Form)<\/strong> based on primary keys<\/strong> requires:<\/p>\n\n\n\n

        \n
      1. The table must first satisfy 1NF<\/strong> (no repeating groups).<\/li>\n\n\n\n
      2. No partial dependency<\/strong> should exist, meaning no non-prime attribute should depend on only part of a composite primary key.<\/li>\n<\/ol>\n\n\n\n

        3NF (Third Normal Form)<\/strong> based on primary keys<\/strong> requires:<\/p>\n\n\n\n

          \n
        1. The table must satisfy 2NF<\/strong>.<\/li>\n\n\n\n
        2. There should be no transitive dependency<\/strong>; non-prime attributes must depend directly on the primary key, not on another non-prime attribute.<\/li>\n<\/ol>\n\n\n\n

          Example<\/strong>:
          Consider a table for Orders<\/code> with OrderID<\/code>, ProductID<\/code>, ProductName<\/code>, Price<\/code>, and Quantity<\/code> as columns, where OrderID<\/code> and ProductID<\/code> together form the composite primary key.<\/p>\n\n\n\n

          OrderID<\/th>ProductID<\/th>ProductName<\/th>Price<\/th>Quantity<\/th><\/tr><\/thead>
          1<\/td>101<\/td>Apple<\/td>2<\/td>10<\/td><\/tr>
          1<\/td>102<\/td>Banana<\/td>1<\/td>5<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n

          In this case, ProductName<\/code> and Price<\/code> depend on ProductID<\/code>, not OrderID<\/code>. These are partial dependencies<\/strong> and violate 2NF<\/strong> based on primary keys. To correct this, we would split the table into:<\/p>\n\n\n\n

            \n
          1. Orders<\/code> (OrderID, ProductID, Quantity)<\/li>\n\n\n\n
          2. Products<\/code> (ProductID, ProductName, Price)<\/li>\n<\/ol>\n\n\n\n

            Now the table is in 2NF<\/strong>.<\/p>\n\n\n\n

            To bring it to 3NF<\/strong>, we also ensure that there are no transitive dependencies (for example, where Price<\/code> depends on ProductID<\/code>, which depends on OrderID<\/code>).<\/p>\n\n\n\n

            By splitting and adjusting tables properly, we can avoid partial and transitive dependencies, ensuring 2NF and 3NF compliance based on primary keys.<\/p>\n","protected":false},"excerpt":{"rendered":"

            The Correct Answer and Explanation is : 1. Transitive Dependency and Its Relation to 3NF Transitive Dependency occurs when one non-prime attribute (a column not part of any candidate key) depends on another non-prime attribute through a third non-prime attribute. In other words, a transitive dependency happens when an attribute indirectly depends on the primary […]<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"footnotes":""},"categories":[25],"tags":[],"class_list":["post-189842","post","type-post","status-publish","format-standard","hentry","category-exams-certification"],"_links":{"self":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/189842","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/comments?post=189842"}],"version-history":[{"count":0,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/189842\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/media?parent=189842"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/categories?post=189842"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/tags?post=189842"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}