{"id":1038,"date":"2024-07-31T10:15:47","date_gmt":"2024-07-31T08:15:47","guid":{"rendered":"https:\/\/blog.sutilweb.eu\/?page_id=1038"},"modified":"2024-07-31T10:15:47","modified_gmt":"2024-07-31T08:15:47","slug":"11-modelo-entidad-relacion","status":"publish","type":"page","link":"https:\/\/sutilweb.eu\/index.php\/databases\/diseno-de-bases-de-datos\/11-modelo-entidad-relacion\/","title":{"rendered":"11. Modelo Entidad-Relaci\u00f3n"},"content":{"rendered":"\n<p>Un <strong>Modelo Entidad-Relaci\u00f3n<\/strong> es un <strong>diagrama<\/strong> que va a ser una herramienta para el <strong>modelado de datos<\/strong>, el cual va a facilitar la representaci\u00f3n de las <strong>entidades<\/strong> en una <strong>base de datos<\/strong>, y cuales van a ser sus <strong>relaciones.<\/strong> Se caracteriza por utilizar una serie de <strong>s\u00edmbolos<\/strong> y <strong>reglas<\/strong> para representar los datos con sus respectivas relaciones. Con este modelo conseguimos representar de forma gr\u00e1fica la <strong>estructura<\/strong> y la <strong>l\u00f3gica<\/strong> de una <strong>base de datos.<\/strong><\/p>\n\n\n\n<!--more-->\n\n\n\n<figure class=\"wp-block-image size-full\"><img loading=\"lazy\" decoding=\"async\" width=\"830\" height=\"540\" src=\"https:\/\/blog.sutilweb.eu\/wp-content\/uploads\/2024\/07\/Modelo-Entidad-Relacion-1.jpg\" alt=\"\" class=\"wp-image-1042\" srcset=\"https:\/\/sutilweb.eu\/wp-content\/uploads\/2024\/07\/Modelo-Entidad-Relacion-1.jpg 830w, https:\/\/sutilweb.eu\/wp-content\/uploads\/2024\/07\/Modelo-Entidad-Relacion-1-300x195.jpg 300w, https:\/\/sutilweb.eu\/wp-content\/uploads\/2024\/07\/Modelo-Entidad-Relacion-1-768x500.jpg 768w\" sizes=\"auto, (max-width: 830px) 100vw, 830px\" \/><\/figure>\n\n\n\n<p>En este ejm, las <strong>entidades<\/strong> van a estar representadas por <strong>rect\u00e1ngulos,<\/strong> tenemos 4 entidades (autor, libro, usuario y ejemplar). Los <strong>\u00f3valos<\/strong> representan los <strong>atributos,<\/strong> es decir, la informaci\u00f3n que necesitamos almacenar en cada <strong>entidad<\/strong> (c\u00f3digo, nombre, tel\u00e9fono y direcci\u00f3n en la entidad usuario). En cada <strong>entidad<\/strong> hay un <strong>atributo<\/strong> que est\u00e1 <strong>subrayado,<\/strong> va a ser la <strong>llave primaria.<\/strong><\/p>\n\n\n\n<p>Entre cada <strong>entidad<\/strong> existe un <strong>rombo,<\/strong> \u00e9ste representa la <strong>relaci\u00f3n<\/strong> que hay entre una ent<strong>i<\/strong>dad y otra. Se va a utilizar un verbo que pueda vincular esa <strong>relaci\u00f3n<\/strong> entre una <strong>entidad<\/strong> y otra.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Modelo relacional<\/h2>\n\n\n\n<p>Existe otro <strong>modelo<\/strong> denominado <strong>modelo relacional<\/strong> de la <strong>base de datos,<\/strong> y tiene la siguiente forma.<\/p>\n\n\n\n<figure class=\"wp-block-image size-full\"><img loading=\"lazy\" decoding=\"async\" width=\"601\" height=\"351\" src=\"https:\/\/blog.sutilweb.eu\/wp-content\/uploads\/2024\/07\/Modelo-Entidad-Relacion-2.jpg\" alt=\"\" class=\"wp-image-1041\" srcset=\"https:\/\/sutilweb.eu\/wp-content\/uploads\/2024\/07\/Modelo-Entidad-Relacion-2.jpg 601w, https:\/\/sutilweb.eu\/wp-content\/uploads\/2024\/07\/Modelo-Entidad-Relacion-2-300x175.jpg 300w\" sizes=\"auto, (max-width: 601px) 100vw, 601px\" \/><\/figure>\n\n\n\n<p>Tenemos varias entidades llamadas <strong>Supplier, Product, Order&#8230;<\/strong> Las <strong>entidades<\/strong> en <strong>SQL<\/strong> se las denomina <strong>tablas,<\/strong> que son como <strong>hojas de c\u00e1lculo<\/strong> donde vamos a almacenar la informaci\u00f3n. En cambio si utilizamos un <strong>modelo no relacional,<\/strong> las <strong>entidades<\/strong> se convierten en <strong>documentos.<\/strong><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Un Modelo Entidad-Relaci\u00f3n es un diagrama que va a ser una herramienta para el modelado de datos, el cual va [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":1009,"menu_order":10,"comment_status":"closed","ping_status":"closed","template":"","meta":{"_uag_custom_page_level_css":"","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":"var(--ast-global-color-4)","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":""},"class_list":["post-1038","page","type-page","status-publish","hentry"],"uagb_featured_image_src":{"full":false,"thumbnail":false,"medium":false,"medium_large":false,"large":false,"1536x1536":false,"2048x2048":false},"uagb_author_info":{"display_name":"Sutil Web","author_link":"https:\/\/sutilweb.eu\/index.php\/author\/sutilweb\/"},"uagb_comment_info":0,"uagb_excerpt":"Un Modelo Entidad-Relaci\u00f3n es un diagrama que va a ser una herramienta para el modelado de datos, el cual va [&hellip;]","_links":{"self":[{"href":"https:\/\/sutilweb.eu\/index.php\/wp-json\/wp\/v2\/pages\/1038","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/sutilweb.eu\/index.php\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/sutilweb.eu\/index.php\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/sutilweb.eu\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/sutilweb.eu\/index.php\/wp-json\/wp\/v2\/comments?post=1038"}],"version-history":[{"count":2,"href":"https:\/\/sutilweb.eu\/index.php\/wp-json\/wp\/v2\/pages\/1038\/revisions"}],"predecessor-version":[{"id":1043,"href":"https:\/\/sutilweb.eu\/index.php\/wp-json\/wp\/v2\/pages\/1038\/revisions\/1043"}],"up":[{"embeddable":true,"href":"https:\/\/sutilweb.eu\/index.php\/wp-json\/wp\/v2\/pages\/1009"}],"wp:attachment":[{"href":"https:\/\/sutilweb.eu\/index.php\/wp-json\/wp\/v2\/media?parent=1038"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}