{"id":1140,"date":"2024-07-31T11:26:47","date_gmt":"2024-07-31T09:26:47","guid":{"rendered":"https:\/\/blog.sutilweb.eu\/?page_id=1140"},"modified":"2024-07-31T11:26:47","modified_gmt":"2024-07-31T09:26:47","slug":"28-llaves-foraneas","status":"publish","type":"page","link":"https:\/\/sutilweb.eu\/index.php\/databases\/sql\/28-llaves-foraneas\/","title":{"rendered":"28. Llaves for\u00e1neas"},"content":{"rendered":"\n<p>Para aprender a manejar consultas <strong>JOIN,<\/strong> antes vamos a crear varias <strong>tablas,<\/strong> que dependan unas de otras, mediante <strong>claves for\u00e1neas<\/strong>. Veamos un ejm del mismo. La sintaxis ser\u00eda.<\/p>\n\n\n\n<!--more-->\n\n\n\n<p><strong>Ejm<\/strong><\/p>\n\n\n\n<pre class=\"wp-block-preformatted\">CREATE DATABASE musica;\n\nUSE musica;\n\nCREATE TABLE estilos ( \nestilo_id INT UNSIGNED AUTO_INCREMENTE PRIMARY KEY, \nestilo VARCHAR(50) NOT NULL\n); \n\nCREATE TABLE paises ( \npais_id INT UNSIGNED AUTO_INCREMENT PRIMARY KEY, \npais VARCHAR(50) NOT NULL\n);\n\nCREATE TABLE bandas (\nbanda_id INT UNSIGNED AUTO_INCREMENT PRIMARY KEY,\nnombre VARCHAR(50),\nestilo_id INT UNSIGNED,\npais_id INT UNSIGNED,\nbio VARCHAR(100);\nFOREIGN KEY(estilo_id) REFERENCES estilos(estilo_id),\nFOREIGN KEY(pais_id) REFERENCES paises(pais_id)\n);<\/pre>\n","protected":false},"excerpt":{"rendered":"<p>Para aprender a manejar consultas JOIN, antes vamos a crear varias tablas, que dependan unas de otras, mediante claves for\u00e1neas. [&hellip;]<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":1076,"menu_order":27,"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-1140","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":"Para aprender a manejar consultas JOIN, antes vamos a crear varias tablas, que dependan unas de otras, mediante claves for\u00e1neas. [&hellip;]","_links":{"self":[{"href":"https:\/\/sutilweb.eu\/index.php\/wp-json\/wp\/v2\/pages\/1140","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=1140"}],"version-history":[{"count":1,"href":"https:\/\/sutilweb.eu\/index.php\/wp-json\/wp\/v2\/pages\/1140\/revisions"}],"predecessor-version":[{"id":1141,"href":"https:\/\/sutilweb.eu\/index.php\/wp-json\/wp\/v2\/pages\/1140\/revisions\/1141"}],"up":[{"embeddable":true,"href":"https:\/\/sutilweb.eu\/index.php\/wp-json\/wp\/v2\/pages\/1076"}],"wp:attachment":[{"href":"https:\/\/sutilweb.eu\/index.php\/wp-json\/wp\/v2\/media?parent=1140"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}