{"id":1772,"date":"2024-08-03T08:16:51","date_gmt":"2024-08-03T06:16:51","guid":{"rendered":"https:\/\/blog.sutilweb.eu\/?page_id=1772"},"modified":"2024-08-03T08:16:52","modified_gmt":"2024-08-03T06:16:52","slug":"10-introduccion-a-mysql","status":"publish","type":"page","link":"https:\/\/sutilweb.eu\/index.php\/lenguajes\/php\/poo-php\/10-introduccion-a-mysql\/","title":{"rendered":"10. Introducci\u00f3n a MySQL"},"content":{"rendered":"\n<p class=\"wp-block-paragraph\">Las <strong>bases de datos<\/strong> no son m\u00e1s que un conjunto de datos&nbsp; que nos van a generar informaci\u00f3n. <strong>MySQL<\/strong> es un software que nos ayuda a gestionar dicha informaci\u00f3n.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Caracter\u00edsticas de MySQL<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Las caracter\u00edsticas de este&nbsp;<strong>gestor de base de datos<\/strong>&nbsp;son las siguientes:<\/p>\n\n\n\n<!--more-->\n\n\n\n<ul class=\"wp-block-list\">\n<li>Es lo que se denomina un\u00a0<strong>SGBD<\/strong>\u00a0(<strong>Sistema de Gesti\u00f3n de Bases de Datos<\/strong>). Lo que hace\u00a0<strong>MySQL<\/strong>\u00a0es\u00a0<strong>gestionar informaci\u00f3n<\/strong>.<\/li>\n\n\n\n<li>Est\u00e1 basado en el lenguaje\u00a0<strong>SQL<\/strong>\u00a0(<strong>Structure Query Language<\/strong>\u00a0\u2013\u00a0<strong>Lenguaje de consulta estructurado<\/strong>).<\/li>\n\n\n\n<li>Es\u00a0<strong>transaccional<\/strong>\u00a0y\u00a0<strong>relacional<\/strong>,\u00a0<strong>transaccional<\/strong>\u00a0lo que significa que se pueden realizar una o varias instrucciones, y si en alg\u00fan momento de esas instrucciones algo falla, se puede regresar a antes de esa transacci\u00f3n. Es\u00a0<strong>relacional<\/strong>\u00a0porque permite tener cierta relaci\u00f3n entre nuestros datos.<\/li>\n\n\n\n<li>La informaci\u00f3n se almacena en objetos llamados <strong>bases de datos<\/strong>, a su vez las <strong>bases de datos<\/strong> tienen objetos llamados <strong>tablas<\/strong>, y las tablas van a tener <strong>campos<\/strong> (datos sueltos) y <strong>registros<\/strong> (conjuntos de datos que generan informaci\u00f3n)<strong>.<\/strong><\/li>\n\n\n\n<li>MySQL cuenta con diferentes motores de tablas (algoritmo que permite trabajar sobre los datos de las tablas). Los mas famosos son <strong>MyISAM<\/strong> e <strong>InnoDB<\/strong>. Las\u00a0<strong>tablas<\/strong>\u00a0pueden ser, o bien\u00a0<strong>planas<\/strong>\u00a0(<strong>MyISAM<\/strong>), que es como si trabajamos con una hoja de c\u00e1lculo de\u00a0<strong>Excel<\/strong>, las cuales NO permiten tener relaciones con otras\u00a0<strong>tablas<\/strong>, este es el motor por defecto de tablas de\u00a0<strong>MySQL<\/strong>. O bien\u00a0<strong>relacionales<\/strong>\u00a0(<strong>InnoDB<\/strong>), con las cuales podemos establecer relaciones con otras tablas. Si lo \u00fanico que estamos pensando es crear una aplicaci\u00f3n que almacene informaci\u00f3n, y despu\u00e9s desplegarla de manera din\u00e1mica, entonces lo mejor es utilizar tablas planas (MyISAM), pero si vamos a utilizar tablas que posean ciertas relaciones, en este caso es mejor trabajar con tablas relacionales.<\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">En los \u00faltimos a\u00f1os se est\u00e1 hablando mucho de <strong>NOSQL<\/strong> (<strong>no s\u00f3lamente SQL<\/strong>) donde existen bases de datos como&nbsp;<a href=\"https:\/\/www.mongodb.com\/cloud\/atlas\/lp\/try4?utm_source=google&amp;utm_campaign=search_gs_pl_evergreen_atlas_core_prosp-brand_gic-null_emea-es_ps-all_desktop_eng_lead&amp;utm_term=mongodb&amp;utm_medium=cpc_paid_search&amp;utm_ad=e&amp;utm_ad_campaign_id=12212624563&amp;adgroup=115749706983&amp;cq_cmp=12212624563&amp;gclid=CjwKCAjwrdmhBhBBEiwA4Hx5g5SuMJlys-KNwvAPqyKKHwjfaPROT9LnT17bvQ5jiRKlbBZMIpxrZRoCfwwQAvD_BwE\" target=\"_blank\" rel=\"noreferrer noopener\"><strong>Mongo DB<\/strong><\/a>, que son documentales, como&nbsp;<a href=\"https:\/\/redis.com\/blog\/database-trigger-features\/?utm_source=google&amp;utm_medium=cpc&amp;utm_term=database%20in%20redis&amp;utm_campaign=redis360-tofu-audiences-emea-19745582853&amp;utm_content=database-trigger-features&amp;gclid=CjwKCAjwrdmhBhBBEiwA4Hx5g-Swy5OwP-Aht4LNxs87pebTdFgYmJU5abxGVWomHn9rY2L8anS8mRoC_nEQAvD_BwE\" target=\"_blank\" rel=\"noreferrer noopener\"><strong>Redis<\/strong><\/a>&nbsp;o&nbsp;<strong>Casandra<\/strong>&nbsp;que son de tipo&nbsp;<strong>clave \u2013 valor<\/strong>, de tipo&nbsp;<a href=\"https:\/\/www.json.org\/json-es.html\" target=\"_blank\" rel=\"noreferrer noopener\"><strong>JSON<\/strong><\/a>.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Links de inter\u00e9s<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">He aqu\u00ed algunos sitios de inter\u00e9s para aquellos que quieran ahondar m\u00e1s en este software.<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><a href=\"https:\/\/www.mysql.com\/\" target=\"_blank\" rel=\"noreferrer noopener\">https:\/\/www.mysql.com\/<\/a><\/li>\n\n\n\n<li><a href=\"https:\/\/conclase.net\/mysql\/curso#gsc.tab=0\" target=\"_blank\" rel=\"noreferrer noopener\">https:\/\/conclase.net\/mysql\/curso#gsc.tab=0<\/a><\/li>\n<\/ul>\n\n\n\n<h2 class=\"wp-block-heading\">Herramientas de gesti\u00f3n de MySQL<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Hay muchas herramientas, unas son de pago, otras gratuitas, algunos ejms son:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Terminal de comandos<\/strong><\/li>\n\n\n\n<li><a href=\"https:\/\/www.navicat.com\/en\/download\/navicat-premium?gclid=CjwKCAjwrdmhBhBBEiwA4Hx5g63f8uBBTUMlDROjd1ZXdXcb06YlmHW5t0aOYEwxxNlwKpmrbBToihoCmTYQAvD_BwE\" target=\"_blank\" rel=\"noreferrer noopener\"><strong>Navicat<\/strong><\/a><\/li>\n\n\n\n<li><a href=\"https:\/\/www.phpmyadmin.net\/\" target=\"_blank\" rel=\"noreferrer noopener\"><strong>phpMyAdmin<\/strong><\/a><\/li>\n<\/ul>\n\n\n\n<p class=\"wp-block-paragraph\">Podemos acceder directamente desde la&nbsp;<strong>terminal<\/strong>, para acceder a&nbsp;<strong>MySQL<\/strong>&nbsp;desde la terminal tenemos que seguir la siguiente ruta:<\/p>\n\n\n\n<pre class=\"wp-block-preformatted\">cd \/ruta-a-directorio\/mysql\/bin<\/pre>\n\n\n\n<p class=\"wp-block-paragraph\">Ahora en muchas ocasiones encontraremos en vez de&nbsp;<strong>MySQL<\/strong>,&nbsp;<a href=\"https:\/\/mariadb.com\/\" target=\"_blank\" rel=\"noreferrer noopener\"><strong>MariaDB<\/strong><\/a>, es lo mismo.<\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Ver las bases de datos<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Se utiliza el comando&nbsp;<strong><em>SHOW DATABASES;<\/em><\/strong><\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Cambiar de base de datos<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">El comando que se utiliza es&nbsp;<strong><em>USE<\/em><\/strong>, de la siguiente manera:<\/p>\n\n\n\n<pre class=\"wp-block-preformatted\">USE base_de_datos<\/pre>\n\n\n\n<h2 class=\"wp-block-heading\">Ver las tablas de una base de datos<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Para ello se ejecuta el comando&nbsp;<strong><em>SHOW TABLES;<\/em><\/strong><\/p>\n\n\n\n<h2 class=\"wp-block-heading\">Mostrar los campos de una tabla<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Se utiliza el comando&nbsp;<strong><em>SELECT<\/em><\/strong>, de la siguiente manera.<\/p>\n\n\n\n<pre class=\"wp-block-preformatted\">SELECT * FROM tabla;<\/pre>\n\n\n\n<h2 class=\"wp-block-heading\">Ver la estructura de una tabla<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Para ello se utiliza el comando&nbsp;<strong><em>DESCRIBE;<\/em><\/strong><\/p>\n\n\n\n<pre class=\"wp-block-preformatted\">DESCRIBE nombre_tabla;<\/pre>\n\n\n\n<h2 class=\"wp-block-heading\">Tipos de sentencias SQL en MySQL<\/h2>\n\n\n\n<p class=\"wp-block-paragraph\">Encontramos dos tipos de sentencias:<\/p>\n\n\n\n<ul class=\"wp-block-list\">\n<li>Comandos para trabajar con <strong>Objetos<\/strong>\u00a0(<strong>bases de datos<\/strong>,\u00a0<strong>tablas<\/strong>,\u00a0<strong>usuarios<\/strong>\u00a0y sus\u00a0<strong>privilegios<\/strong>).<\/li>\n\n\n\n<li>Comandos trabajar con <strong>Datos<\/strong>\u00a0(<strong>CRUD<\/strong>\u00a0\u2013\u00a0<strong>Create, Read, Update, Delete<\/strong>).<\/li>\n<\/ul>\n","protected":false},"excerpt":{"rendered":"<p>Las bases de datos no son m\u00e1s que un conjunto de datos&nbsp; que nos van a generar informaci\u00f3n. MySQL es un software que nos ayuda a gestionar dicha informaci\u00f3n. Caracter\u00edsticas de MySQL Las caracter\u00edsticas de este&nbsp;gestor de base de datos&nbsp;son las siguientes:<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":1735,"menu_order":9,"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-1772","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":"Las bases de datos no son m\u00e1s que un conjunto de datos&nbsp; que nos van a generar informaci\u00f3n. MySQL es un software que nos ayuda a gestionar dicha informaci\u00f3n. Caracter\u00edsticas de MySQL Las caracter\u00edsticas de este&nbsp;gestor de base de datos&nbsp;son las siguientes:","_links":{"self":[{"href":"https:\/\/sutilweb.eu\/index.php\/wp-json\/wp\/v2\/pages\/1772","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=1772"}],"version-history":[{"count":2,"href":"https:\/\/sutilweb.eu\/index.php\/wp-json\/wp\/v2\/pages\/1772\/revisions"}],"predecessor-version":[{"id":1774,"href":"https:\/\/sutilweb.eu\/index.php\/wp-json\/wp\/v2\/pages\/1772\/revisions\/1774"}],"up":[{"embeddable":true,"href":"https:\/\/sutilweb.eu\/index.php\/wp-json\/wp\/v2\/pages\/1735"}],"wp:attachment":[{"href":"https:\/\/sutilweb.eu\/index.php\/wp-json\/wp\/v2\/media?parent=1772"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}