{"id":180829,"date":"2025-01-09T05:36:53","date_gmt":"2025-01-09T05:36:53","guid":{"rendered":"https:\/\/learnexams.com\/blog\/?p=180829"},"modified":"2025-01-09T05:36:55","modified_gmt":"2025-01-09T05:36:55","slug":"which-one-of-the-following-statements-about-normal-forms-is-false","status":"publish","type":"post","link":"https:\/\/www.learnexams.com\/blog\/2025\/01\/09\/which-one-of-the-following-statements-about-normal-forms-is-false\/","title":{"rendered":"Which one of the following statements about normal forms is FALSE"},"content":{"rendered":"\n

Which one of the following statements about normal forms is FALSE? (A) BCNF is stricter than 3NF (B) Lossless, dependency-preserving decomposi\u00adtion into 3NF is always possible (C) Lossless, dependency-preserving decomposi\u00adtion into BCNF is always possible (D) Any relation with two attributes is in BCNF<\/p>\n\n\n\n

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

Correct Answer: (C) Lossless, dependency-preserving decomposition into BCNF is always possible<\/strong><\/h3>\n\n\n\n
\n\n\n\n

Explanation:<\/h3>\n\n\n\n

Normal Forms Overview<\/strong>:<\/h4>\n\n\n\n
    \n
  • First Normal Form (1NF)<\/strong>: A relation is in 1NF if all attributes contain only atomic (indivisible) values.<\/li>\n\n\n\n
  • Second Normal Form (2NF)<\/strong>: A relation is in 2NF if it is in 1NF and has no partial dependencies (no attribute depends only on part of a candidate key).<\/li>\n\n\n\n
  • Third Normal Form (3NF)<\/strong>: A relation is in 3NF if it is in 2NF and has no transitive dependencies (non-prime attributes depend only on candidate keys).<\/li>\n\n\n\n
  • Boyce-Codd Normal Form (BCNF)<\/strong>: A stricter version of 3NF, where every determinant is a candidate key.<\/li>\n<\/ul>\n\n\n\n
    \n\n\n\n

    Why the Answer is False<\/strong>:<\/h4>\n\n\n\n
      \n
    1. Option (A): BCNF is stricter than 3NF<\/strong>
      This is true. BCNF is a stronger normal form than 3NF because all relations in BCNF are also in 3NF, but not all 3NF relations are in BCNF. BCNF eliminates situations where a non-candidate key attribute acts as a determinant.<\/li>\n\n\n\n
    2. Option (B): Lossless, dependency-preserving decomposition into 3NF is always possible<\/strong>
      This is true. A relation can always be decomposed into 3NF in a way that preserves all functional dependencies and ensures the decomposition is lossless.<\/li>\n\n\n\n
    3. Option (C): Lossless, dependency-preserving decomposition into BCNF is always possible<\/strong>
      This is false. While a lossless decomposition into BCNF is always possible, it may not preserve all functional dependencies. For example, if a relation has a dependency that violates BCNF but is crucial for query optimization, decomposing into BCNF may lose that dependency.<\/li>\n\n\n\n
    4. Option (D): Any relation with two attributes is in BCNF<\/strong>
      This is true. A two-attribute relation can always satisfy BCNF because any functional dependency in such a relation would involve both attributes, making both candidate keys.<\/li>\n<\/ol>\n\n\n\n
      \n\n\n\n

      Key Takeaway<\/strong>:<\/h4>\n\n\n\n

      Lossless, dependency-preserving decomposition into BCNF is not always achievable<\/strong>, making option (C) false. This is an important limitation of BCNF compared to 3NF, which guarantees both properties.<\/p>\n","protected":false},"excerpt":{"rendered":"

      Which one of the following statements about normal forms is FALSE? (A) BCNF is stricter than 3NF (B) Lossless, dependency-preserving decomposi\u00adtion into 3NF is always possible (C) Lossless, dependency-preserving decomposi\u00adtion into BCNF is always possible (D) Any relation with two attributes is in BCNF The Correct Answer and Explanation is : Correct Answer: (C) Lossless, […]<\/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-180829","post","type-post","status-publish","format-standard","hentry","category-exams-certification"],"_links":{"self":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/180829","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=180829"}],"version-history":[{"count":0,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/posts\/180829\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/media?parent=180829"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/categories?post=180829"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.learnexams.com\/blog\/wp-json\/wp\/v2\/tags?post=180829"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}