{"id":51,"date":"2019-09-09T12:19:13","date_gmt":"2019-09-09T12:19:13","guid":{"rendered":"http:\/\/learnlearn.uk\/alevelcs\/?page_id=51"},"modified":"2021-04-24T07:31:51","modified_gmt":"2021-04-24T07:31:51","slug":"1st-2nd-3rd-normal-form","status":"publish","type":"page","link":"https:\/\/learnlearn.uk\/alevelcs\/1st-2nd-3rd-normal-form\/","title":{"rendered":"1st, 2nd and 3rd normal form"},"content":{"rendered":"<div class=\"responsive-tabs\">\n<h2 class=\"tabtitle\">Normalisation<\/h2>\n<div class=\"tabcontent\">\n\n<h3>Database Normalisation<\/h3>\n<p>Normalisation is the process of removing redundancy within a database.<\/p>\n<p>Doing so:<\/p>\n<ul>\n<li>Makes accessing and storing data easier and more efficient<\/li>\n<li>Makes maintaining the database contents quicker and easier<\/li>\n<li>Reduces the chances of data errors or duplication.<\/li>\n<\/ul>\n<p>In order to a achieve this a set of rules were established to achieve efficiency &#8211; <strong>1st, 2nd and 3rd normal form<\/strong>. Each rule builds on the last rule, but think of it as a mental process that you go through to improve your database.<\/p>\n\n<\/div><h2 class=\"tabtitle\">Tutorial Video<\/h2>\n<div class=\"tabcontent\">\n\n<h3>Tutorial Video<\/h3>\n<div class=\"nv-iframe-embed\">\n<div class=\"container-lazyload preview-lazyload container-youtube js-lazyload--not-loaded\"><a href=\"https:\/\/www.youtube.com\/watch?v=J-drts33N8g\" class=\"lazy-load-youtube preview-lazyload preview-youtube\" data-video-title=\"1st, 2nd and 3rd Normal Form (Database Normalisation)\" title=\"Play video &quot;1st, 2nd and 3rd Normal Form (Database Normalisation)&quot;\">https:\/\/www.youtube.com\/watch?v=J-drts33N8g<\/a><noscript>Video can&#8217;t be loaded because JavaScript is disabled: <a href=\"https:\/\/www.youtube.com\/watch?v=J-drts33N8g\" title=\"1st, 2nd and 3rd Normal Form (Database Normalisation)\">1st, 2nd and 3rd Normal Form (Database Normalisation) (https:\/\/www.youtube.com\/watch?v=J-drts33N8g)<\/a><\/noscript><\/div>\n<\/div>\n<p><a href=\"https:\/\/drive.google.com\/file\/d\/1ZhF0l8YkRJc09Job3bg4de0sOVIUzxCn\/view?usp=sharing\">Can&#8217;t access YouTube? Click Here for the Google Drive version.<\/a><\/p>\n\n<\/div><h2 class=\"tabtitle\">1NF<\/h2>\n<div class=\"tabcontent\">\n\n<h3>First Normal Form <span style=\"color: #0000ff;\">&#8220;Unique and atomic values&#8221;<\/span><\/h3>\n<ul>\n<li>Each Row in a database must be unique\n<ul>\n<li>Easily achieved through the use of a Primary Key<\/li>\n<\/ul>\n<\/li>\n<li>All cells must only contain one piece of data (no arrays stored in a cell)<\/li>\n<li>All column data must be of the same type<\/li>\n<\/ul>\n<p>&nbsp;<\/p>\n\n<\/div><h2 class=\"tabtitle\">2NF<\/h2>\n<div class=\"tabcontent\">\n\n<h3>Second Normal Form <span style=\"color: #0000ff;\">&#8220;No Partial Dependencies&#8221;<\/span><\/h3>\n<ul>\n<li>This is only applicable if the\u00a0 table contains a composite key.<\/li>\n<li>The database must be in First Normal Form<\/li>\n<li>All columns within a table must depend on the whole key (No partial Dependency).<\/li>\n<\/ul>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n\n<\/div><h2 class=\"tabtitle\">3NF<\/h2>\n<div class=\"tabcontent\">\n\n<p><strong>Third Normal Form <span style=\"color: #0000ff;\">&#8220;No Transitive Dependencies&#8221;<\/span><\/strong><\/p>\n<ul>\n<li>The database must be in Second Normal Form<\/li>\n<li>All fields must only be determinable directly by the primary key (no transitive dependency)<\/li>\n<\/ul>\n<table class=\"wikitable\">\n<tbody>\n<tr>\n<th>Book<\/th>\n<th>Genre<\/th>\n<th>Author<\/th>\n<th>Author Nationality<\/th>\n<\/tr>\n<tr>\n<td><i><a title=\"Twenty Thousand Leagues Under the Sea\" href=\"https:\/\/en.wikipedia.org\/wiki\/Twenty_Thousand_Leagues_Under_the_Sea\">Twenty Thousand Leagues Under the Sea<\/a><\/i><\/td>\n<td><a class=\"mw-redirect\" title=\"Science Fiction\" href=\"https:\/\/en.wikipedia.org\/wiki\/Science_Fiction\">Science Fiction<\/a><\/td>\n<td><a title=\"Jules Verne\" href=\"https:\/\/en.wikipedia.org\/wiki\/Jules_Verne\">Jules Verne<\/a><\/td>\n<td><a title=\"French people\" href=\"https:\/\/en.wikipedia.org\/wiki\/French_people\">French<\/a><\/td>\n<\/tr>\n<tr>\n<td><i><a title=\"Journey to the Center of the Earth\" href=\"https:\/\/en.wikipedia.org\/wiki\/Journey_to_the_Center_of_the_Earth\">Journey to the Center of the Earth<\/a><\/i><\/td>\n<td><a class=\"mw-redirect\" title=\"Science Fiction\" href=\"https:\/\/en.wikipedia.org\/wiki\/Science_Fiction\">Science Fiction<\/a><\/td>\n<td><a title=\"Jules Verne\" href=\"https:\/\/en.wikipedia.org\/wiki\/Jules_Verne\">Jules Verne<\/a><\/td>\n<td>French<\/td>\n<\/tr>\n<tr>\n<td><i><a title=\"Leaves of Grass\" href=\"https:\/\/en.wikipedia.org\/wiki\/Leaves_of_Grass\">Leaves of Grass<\/a><\/i><\/td>\n<td><a title=\"Poetry\" href=\"https:\/\/en.wikipedia.org\/wiki\/Poetry\">Poetry<\/a><\/td>\n<td><a title=\"Walt Whitman\" href=\"https:\/\/en.wikipedia.org\/wiki\/Walt_Whitman\">Walt Whitman<\/a><\/td>\n<td><a title=\"United States\" href=\"https:\/\/en.wikipedia.org\/wiki\/United_States\">American<\/a><\/td>\n<\/tr>\n<tr>\n<td><i><a title=\"Anna Karenina\" href=\"https:\/\/en.wikipedia.org\/wiki\/Anna_Karenina\">Anna Karenina<\/a><\/i><\/td>\n<td><a class=\"mw-redirect\" title=\"Literary Fiction\" href=\"https:\/\/en.wikipedia.org\/wiki\/Literary_Fiction\">Literary Fiction<\/a><\/td>\n<td><a title=\"Leo Tolstoy\" href=\"https:\/\/en.wikipedia.org\/wiki\/Leo_Tolstoy\">Leo Tolstoy<\/a><\/td>\n<td><a title=\"Russians\" href=\"https:\/\/en.wikipedia.org\/wiki\/Russians\">Russian<\/a><\/td>\n<\/tr>\n<tr>\n<td><i><a title=\"A Confession\" href=\"https:\/\/en.wikipedia.org\/wiki\/A_Confession\">A Confession<\/a><\/i><\/td>\n<td><a class=\"new\" title=\"Religious Autobiography (page does not exist)\" href=\"https:\/\/en.wikipedia.org\/w\/index.php?title=Religious_Autobiography&amp;action=edit&amp;redlink=1\">Religious Autobiography<\/a><\/td>\n<td><a title=\"Leo Tolstoy\" href=\"https:\/\/en.wikipedia.org\/wiki\/Leo_Tolstoy\">Leo Tolstoy<\/a><\/td>\n<td>Russian<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<p>In the table above the Author Nationality is dependent on the Book only via the Author<\/p>\n<p>&#8220;The author of the book is French because the author of the book is Jules Verne&#8221;<\/p>\n<p>Author Nationality\u00a0 \u00a0&#8212;-&gt;\u00a0 Author\u00a0 &#8212;-&gt; Book<\/p>\n<p>&nbsp;<\/p>\n<p>A great video explaining the process &#8211;\u00a0<a href=\"https:\/\/www.youtube.com\/watch?v=UrYLYV7WSHM\">https:\/\/www.youtube.com\/watch?v=UrYLYV7WSHM<\/a><\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n\n<\/div><h2 class=\"tabtitle\">Resources<\/h2>\n<div class=\"tabcontent\">\n\n<p><a href=\"https:\/\/docs.google.com\/presentation\/d\/1dJH-v1VfdUxdKsbs7KkFtBdePOpMGIalsu2GjrqOqsA\/edit?usp=sharing\">Teacher Presentation<\/a><\/p>\n<p><a href=\"https:\/\/www.cambridgeinternational.org\/Images\/524462-june-2017-question-paper-11.pdf\">Past paper questions 1 &#8211;\u00a0 (pages 2 &#8211; 3)<\/a><\/p>\n<p><a href=\"https:\/\/www.cambridgeinternational.org\/Images\/129845-2015-paper-1-specimen-paper.pdf\">Past paper questions 2- (pages 2 &#8211; 4)<\/a>\u00a0 &#8211; Includes questions on 1nf,3nf<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<p>&nbsp;<\/p>\n<\/div><\/div>\n<p>&nbsp;<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Database Normalisation Normalisation is the process of removing redundancy within a database. Doing so: Makes accessing and storing data easier and more efficient Makes maintaining the database contents quicker and easier Reduces the chances of data errors or duplication. In order to a achieve this a set of rules were established to achieve efficiency &#8211;&hellip;&nbsp;<a href=\"https:\/\/learnlearn.uk\/alevelcs\/1st-2nd-3rd-normal-form\/\" class=\"\" rel=\"bookmark\">Read More &raquo;<span class=\"screen-reader-text\">1st, 2nd and 3rd normal form<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"parent":0,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"neve_meta_sidebar":"","neve_meta_container":"","neve_meta_enable_content_width":"","neve_meta_content_width":70,"neve_meta_title_alignment":"","neve_meta_author_avatar":"","neve_post_elements_order":"","neve_meta_disable_header":"","neve_meta_disable_footer":"","neve_meta_disable_title":""},"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v20.6 - https:\/\/yoast.com\/wordpress\/plugins\/seo\/ -->\n<title>1st, 2nd and 3rd normal form - A Level Computer Science<\/title>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/learnlearn.uk\/alevelcs\/1st-2nd-3rd-normal-form\/\" \/>\n<meta property=\"og:locale\" content=\"en_GB\" \/>\n<meta property=\"og:type\" content=\"article\" \/>\n<meta property=\"og:title\" content=\"1st, 2nd and 3rd normal form - A Level Computer Science\" \/>\n<meta property=\"og:description\" content=\"Database Normalisation Normalisation is the process of removing redundancy within a database. 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Doing so: Makes accessing and storing data easier and more efficient Makes maintaining the database contents quicker and easier Reduces the chances of data errors or duplication. In order to a achieve this a set of rules were established to achieve efficiency &#8211;&hellip;&nbsp;Read&hellip;","_links":{"self":[{"href":"https:\/\/learnlearn.uk\/alevelcs\/wp-json\/wp\/v2\/pages\/51"}],"collection":[{"href":"https:\/\/learnlearn.uk\/alevelcs\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/learnlearn.uk\/alevelcs\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/learnlearn.uk\/alevelcs\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/learnlearn.uk\/alevelcs\/wp-json\/wp\/v2\/comments?post=51"}],"version-history":[{"count":11,"href":"https:\/\/learnlearn.uk\/alevelcs\/wp-json\/wp\/v2\/pages\/51\/revisions"}],"predecessor-version":[{"id":1997,"href":"https:\/\/learnlearn.uk\/alevelcs\/wp-json\/wp\/v2\/pages\/51\/revisions\/1997"}],"wp:attachment":[{"href":"https:\/\/learnlearn.uk\/alevelcs\/wp-json\/wp\/v2\/media?parent=51"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}