{"id":1110,"date":"2024-07-31T11:14:57","date_gmt":"2024-07-31T09:14:57","guid":{"rendered":"https:\/\/blog.sutilweb.eu\/?page_id=1110"},"modified":"2024-07-31T11:14:57","modified_gmt":"2024-07-31T09:14:57","slug":"13-creando-tablas","status":"publish","type":"page","link":"https:\/\/sutilweb.eu\/index.php\/databases\/sql\/13-creando-tablas\/","title":{"rendered":"13. Creando tablas"},"content":{"rendered":"\n

En este cap\u00edtulo vamos a ver como crear tablas<\/strong> en nuestras bases de datos.<\/strong> Cuando vayamos a trabajar con una base de datos<\/strong> en particular, tenemos que ejecutar un comando en particular denominado USE,<\/em><\/strong> que le indica al gestor de bases de datos<\/strong> cual de las bases de datos<\/strong> disponible es con la que vamos a trabajar. Para ello utilizamos la siguiente sintaxis.<\/p>\n\n\n\n\n\n\n\n

Ejm<\/strong><\/p>\n\n\n\n

USE curso_sql;<\/pre>\n\n\n\n
Lo que hace es que ahora estamos en la base de datos curso_sql.<\/em><\/p>\n\n\n\n
Ver las tablas de una base de datos<\/h2>\n\n\n\n
Para poder ver las tablas<\/strong> de una base de datos<\/strong> en particular, tenemos que haber seleccionado dicha base de datos con el comando USE,<\/em><\/strong> para posteriormente ejecutar el comando SHOW TABLES<\/em><\/strong>, que tiene la siguiente sintaxis.<\/p>\n\n\n\n
Ejm<\/strong><\/p>\n\n\n\n
SHOW TABLES;<\/pre>\n\n\n\n
Describir las caracter\u00edsticas de una tabla<\/h2>\n\n\n\n
Existe un comando para describir las caracter\u00edsticas de una tabla<\/strong>, se trata del comando DESCRIBE,<\/em><\/strong> que tiene la siguiente sintaxis.<\/p>\n\n\n\n
Ejm<\/strong><\/p>\n\n\n\n
DESCRIBE curso_sql;<\/pre>\n\n\n\n
Crear una tabla<\/h2>\n\n\n\n
Para crear una tabla<\/strong> se utiliza el comando CREATE,<\/em><\/strong> de la siguiente manera.<\/p>\n\n\n\n
CREATE TABLE usuarios(\nnombre VARCHAR(50),\ncorreo VARCHAR(150)\n);<\/pre>\n\n\n\n
Modificar una tabla<\/h2>\n\n\n\n
Para ello se utiliza el comando ALTER TABLE<\/em><\/strong>, de la siguiente manera.<\/p>\n\n\n\n
Ejm<\/strong><\/p>\n\n\n\n
ALTER TABLE usuarios ADD COLUMN apellidos VARCHAR(50);\n\n-- Modificar el tipo de dato apellidos\nALTER TABLE usuarios MODIFY apellidos CHAR(50)\n\n-- Renombramos el campo apellidos\nALTER TABLE usuarios RENAME apellidos TO apellido;\n\n-- Eliminar una columna\nALTER TABLE usuarios DROP COLUMN apellido;<\/pre>\n\n\n\n
Eliminar una tabla<\/h2>\n\n\n\n
Se utiliza el comando DROP,<\/em><\/strong> de la siguiente manera.<\/p>\n\n\n\n
Ejm<\/strong><\/p>\n\n\n\n
DROP TABLE usuarios;<\/pre>\n","protected":false},"excerpt":{"rendered":"
En este cap\u00edtulo vamos a ver como crear tablas en nuestras bases de datos. Cuando vayamos a trabajar con una […]<\/p>\n","protected":false},"author":1,"featured_media":0,"parent":1076,"menu_order":12,"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-1110","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":"En este cap\u00edtulo vamos a ver como crear tablas en nuestras bases de datos. Cuando vayamos a trabajar con una […]","_links":{"self":[{"href":"https:\/\/sutilweb.eu\/index.php\/wp-json\/wp\/v2\/pages\/1110","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=1110"}],"version-history":[{"count":1,"href":"https:\/\/sutilweb.eu\/index.php\/wp-json\/wp\/v2\/pages\/1110\/revisions"}],"predecessor-version":[{"id":1111,"href":"https:\/\/sutilweb.eu\/index.php\/wp-json\/wp\/v2\/pages\/1110\/revisions\/1111"}],"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=1110"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}