{"id":70,"date":"2018-09-08T23:38:35","date_gmt":"2018-09-08T23:38:35","guid":{"rendered":"https:\/\/math-brownies.de\/?p=70"},"modified":"2018-11-16T18:34:30","modified_gmt":"2018-11-16T18:34:30","slug":"feinheiten-bei-datenbankabfragen","status":"publish","type":"post","link":"https:\/\/math-brownies.de\/index.php\/2018\/09\/08\/feinheiten-bei-datenbankabfragen\/","title":{"rendered":"Feinheiten bei Datenbankabfragen"},"content":{"rendered":"<ul>\n<li>execute braucht ein Array. (Eckige Klammern)<\/li>\n<li>Man nutzt prepare und excute und die Fragezeichen im Befehl, die dann erst \u00fcber execute gef\u00fcllt werden, weil diese Funktionen checken, ob da nicht jemand in das Eingabefeld eine injektion geschrieben hat. Alles andere stellt eine Sicherheitsl\u00fccke dar. Wenn das zu un\u00fcbersichtlich wird, kann man eine Zwischenvariable, z.B. $data nutzen, die ein Array ist, und ruft dann execute($data) auf.<\/li>\n<li>fetch_column gibt false zur\u00fcck, wenn keine Eintr\u00e4ge gefunden wurden. Man muss eine Variable also nicht extra vorher auf false setzen.<\/li>\n<li>In den SQL-Befhlen nutzt man `ABC` (Das Hochkomma kriegt man mit Umschalt+die Taste rechts von \u00df) , um Tabellen oder Spalten anzusprechen, die Gro\u00dfuchstaben beinhalten. Weniger Stress hat man, wenn man gleich alles mit Kleinbuchstaben macht.<\/li>\n<li>Wenn man in einer Funktion eine Variable nutzen will, die zwar im Klassenkontext zur Verf\u00fcgung steht, aber nicht IN der Funktion explizit gesetzt wurde, muss man diese Variable dort, wo sie mal &#8222;bekannt&#8220; war, mittels $this-&gt;var=bekannter Wert; dem Objekt zuweisen. Dann kann man sie auch wieder mittels $this-var aufrufen in allen Funktionen der Klasse. (Das geht sogar mit dem ganzen Datenbankobjekt.)<\/li>\n<\/ul>\n","protected":false},"excerpt":{"rendered":"<p>execute braucht ein Array. (Eckige Klammern) Man nutzt prepare und excute und die Fragezeichen im Befehl, die dann erst \u00fcber execute gef\u00fcllt werden, weil diese Funktionen checken, ob da nicht jemand in das Eingabefeld eine injektion geschrieben hat. Alles andere stellt eine Sicherheitsl\u00fccke dar. Wenn das zu un\u00fcbersichtlich wird, kann man eine Zwischenvariable, z.B. $data [&hellip;]<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"site-sidebar-layout":"default","site-content-layout":"default","ast-site-content-layout":"","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":"","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":"","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":""},"categories":[4,9,3,5],"tags":[],"class_list":["post-70","post","type-post","status-publish","format-standard","hentry","category-datenbanken","category-datenschutz","category-informatik","category-php"],"_links":{"self":[{"href":"https:\/\/math-brownies.de\/index.php\/wp-json\/wp\/v2\/posts\/70","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/math-brownies.de\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/math-brownies.de\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/math-brownies.de\/index.php\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/math-brownies.de\/index.php\/wp-json\/wp\/v2\/comments?post=70"}],"version-history":[{"count":4,"href":"https:\/\/math-brownies.de\/index.php\/wp-json\/wp\/v2\/posts\/70\/revisions"}],"predecessor-version":[{"id":75,"href":"https:\/\/math-brownies.de\/index.php\/wp-json\/wp\/v2\/posts\/70\/revisions\/75"}],"wp:attachment":[{"href":"https:\/\/math-brownies.de\/index.php\/wp-json\/wp\/v2\/media?parent=70"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/math-brownies.de\/index.php\/wp-json\/wp\/v2\/categories?post=70"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/math-brownies.de\/index.php\/wp-json\/wp\/v2\/tags?post=70"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}