{"id":118,"date":"2013-12-12T11:05:29","date_gmt":"2013-12-12T11:05:29","guid":{"rendered":"http:\/\/it.tuxie.eu\/?p=118"},"modified":"2013-12-12T11:09:38","modified_gmt":"2013-12-12T11:09:38","slug":"alter-table-add-column-s-urcenim-polohy-sloupecku","status":"publish","type":"post","link":"http:\/\/it.tuxie.eu\/?p=118","title":{"rendered":"ALTER TABLE ADD COLUMN s urcenim polohy sloupecku"},"content":{"rendered":"

Kdo by chtel provadet takovou operaci, odporujici relacni algebre a celkovemu navrhu databazi? Nu, treba v situaci, kdy je treba sloupecek dropnout, znovuvytvorit a cert vi, jak jsou SELECTy na aplikacni urovni utvarene (select *…)<\/p>\n

<\/p>\n

Prehled znamych vendoru, kterak se s touto situaci vyporadavaji:<\/p>\n

Neuspech, prostrednicek, vysmech, workaroundy, pobourena komunita<\/span>
\n<\/strong><\/p>\n

\"\"<\/a><\/p>\n

Referencni prirucka pro ALTER TABLE<\/a><\/p>\n

Nic, proste nic. Agresivni komunita premoudrelych OCA, OCP, ORA ACE. Svym zpusobem chapu asi velmi dobre jejich skuceni – ale viz priklad u „dcery“ MySQL – ono to JDE. Ono se to CASTO pouziva, ono je to zadane. A presne po tomhle napsanem – ze to jinde jde, v Oraclu ne – hodne smutne.<\/p>\n

 <\/p>\n

\"\"<\/a><\/p>\n

Referencni prirucka pro ALTER TABLE<\/a><\/p>\n

\"\"<\/a><\/p>\n

Referencni prirucka pro ALTER TABLE<\/a><\/p>\n

\"\"<\/a><\/p>\n

\u00a0Referencni prirucka pro ALTER TABLE<\/a><\/p>\n

 <\/p>\n

Uspech, vyvojari nejsou lini \ud83d\ude42<\/span>
\n<\/strong><\/p>\n

\"\"<\/strong><\/a><\/p>\n

Referencni prirucka pro ALTER TABLE<\/a>. Hura!<\/p>\n

priklad pro pridani sloupecku „count“\u00a0 za jiz existujici „lastname“ sloupec:<\/p>\n

ALTER TABLE ADD COLUMN 'count' SMALLINT(6) NOT NULL AFTER 'lastname'<\/code><\/span><\/p>\n

\"\"<\/strong><\/a><\/p>\n

Referencni prirucka pro ALTER TABLE<\/a>. Hura!<\/p>\n

priklad pro posunuti poradi sloupecku „STOCK“:<\/p>\n

ALTER TABLE STOCK ALTER QUANTITY POSITION 3<\/code><\/p>\n

————–<\/p>\n

Je smutne, ze mnoho vendoru tuto primitivni funkcionalitu ignoruje. Treba u tabulky s 1+ miliardou zaznamu nepadaji do uvahy „moudra“ workaround typu znovuvytvoreni tabulky CREATE TABLE AS SELECT…. a prelivani dat, atd.<\/p>\n

Argumenty ze na poradi sloupcu prece nezalezi a jde jen o „kvalitu“ SELECTu jsou na urovni profesorskeho teoretickeho plkani – zrejme zadni z autoru se nesetkali v praxi s tim, ze SELECTy opravdu neovlivni \ud83d\ude42<\/p>\n

-a-<\/p>\n","protected":false},"excerpt":{"rendered":"

Kdo by chtel provadet takovou operaci, odporujici relacni algebre a celkovemu navrhu databazi? Nu, treba v situaci, kdy je treba sloupecek dropnout, znovuvytvorit a cert vi, jak jsou SELECTy na aplikacni urovni utvarene (select *…)<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":[],"categories":[7],"tags":[],"_links":{"self":[{"href":"http:\/\/it.tuxie.eu\/index.php?rest_route=\/wp\/v2\/posts\/118"}],"collection":[{"href":"http:\/\/it.tuxie.eu\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/it.tuxie.eu\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/it.tuxie.eu\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/it.tuxie.eu\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=118"}],"version-history":[{"count":0,"href":"http:\/\/it.tuxie.eu\/index.php?rest_route=\/wp\/v2\/posts\/118\/revisions"}],"wp:attachment":[{"href":"http:\/\/it.tuxie.eu\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=118"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/it.tuxie.eu\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=118"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/it.tuxie.eu\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=118"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}