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class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--icon-only " aria-hidden="true" ><span class="vector-icon mw-ui-icon-listBullet mw-ui-icon-wikimedia-listBullet"></span> <span class="vector-dropdown-label-text">Mostra/Nascondi l'indice</span> </label> <div class="vector-dropdown-content"> <div id="vector-page-titlebar-toc-unpinned-container" class="vector-unpinned-container"> </div> </div> </div> </nav> <h1 id="firstHeading" class="firstHeading mw-first-heading"><span class="mw-page-title-main">Modello reticolare</span></h1> <div id="p-lang-btn" class="vector-dropdown mw-portlet mw-portlet-lang" > <input type="checkbox" id="p-lang-btn-checkbox" role="button" aria-haspopup="true" data-event-name="ui.dropdown-p-lang-btn" class="vector-dropdown-checkbox mw-interlanguage-selector" aria-label="Vai a una voce in un'altra lingua. Disponibile in 25 lingue" > <label id="p-lang-btn-label" for="p-lang-btn-checkbox" class="vector-dropdown-label cdx-button cdx-button--fake-button cdx-button--fake-button--enabled cdx-button--weight-quiet cdx-button--action-progressive mw-portlet-lang-heading-25" aria-hidden="true" ><span class="vector-icon mw-ui-icon-language-progressive mw-ui-icon-wikimedia-language-progressive"></span> <span class="vector-dropdown-label-text">25 lingue</span> </label> <div class="vector-dropdown-content"> <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li class="interlanguage-link interwiki-ar mw-list-item"><a href="https://ar.wikipedia.org/wiki/%D9%86%D9%85%D9%88%D8%B0%D8%AC_%D8%A7%D9%84%D8%B4%D8%A8%D9%83%D8%A9" title="نموذج الشبكة - arabo" lang="ar" hreflang="ar" data-title="نموذج الشبكة" data-language-autonym="العربية" data-language-local-name="arabo" class="interlanguage-link-target"><span>العربية</span></a></li><li class="interlanguage-link interwiki-az mw-list-item"><a href="https://az.wikipedia.org/wiki/%C5%9E%C9%99b%C9%99k%C9%99_veril%C9%99nl%C9%99r_bazas%C4%B1" title="Şəbəkə verilənlər bazası - azerbaigiano" lang="az" hreflang="az" data-title="Şəbəkə verilənlər bazası" data-language-autonym="Azərbaycanca" data-language-local-name="azerbaigiano" class="interlanguage-link-target"><span>Azərbaycanca</span></a></li><li class="interlanguage-link interwiki-bg mw-list-item"><a href="https://bg.wikipedia.org/wiki/%D0%9C%D1%80%D0%B5%D0%B6%D0%BE%D0%B2_%D0%BC%D0%BE%D0%B4%D0%B5%D0%BB_%D0%BD%D0%B0_%D0%B1%D0%B0%D0%B7%D0%B0_%D0%B4%D0%B0%D0%BD%D0%BD%D0%B8" title="Мрежов модел на база данни - bulgaro" lang="bg" hreflang="bg" data-title="Мрежов модел на база данни" data-language-autonym="Български" data-language-local-name="bulgaro" class="interlanguage-link-target"><span>Български</span></a></li><li class="interlanguage-link interwiki-cs mw-list-item"><a href="https://cs.wikipedia.org/wiki/S%C3%AD%C5%A5ov%C3%A1_datab%C3%A1ze" title="Síťová databáze - ceco" lang="cs" hreflang="cs" data-title="Síťová databáze" data-language-autonym="Čeština" data-language-local-name="ceco" class="interlanguage-link-target"><span>Čeština</span></a></li><li class="interlanguage-link interwiki-de mw-list-item"><a href="https://de.wikipedia.org/wiki/Netzwerkdatenbankmodell" title="Netzwerkdatenbankmodell - tedesco" lang="de" hreflang="de" data-title="Netzwerkdatenbankmodell" data-language-autonym="Deutsch" data-language-local-name="tedesco" class="interlanguage-link-target"><span>Deutsch</span></a></li><li class="interlanguage-link interwiki-en mw-list-item"><a href="https://en.wikipedia.org/wiki/Network_model" title="Network model - inglese" lang="en" hreflang="en" data-title="Network model" data-language-autonym="English" data-language-local-name="inglese" class="interlanguage-link-target"><span>English</span></a></li><li class="interlanguage-link interwiki-es mw-list-item"><a href="https://es.wikipedia.org/wiki/Base_de_datos_de_red" title="Base de datos de red - spagnolo" lang="es" hreflang="es" data-title="Base de datos de red" data-language-autonym="Español" data-language-local-name="spagnolo" class="interlanguage-link-target"><span>Español</span></a></li><li class="interlanguage-link interwiki-fa mw-list-item"><a href="https://fa.wikipedia.org/wiki/%D9%85%D8%AF%D9%84_%D8%B4%D8%A8%DA%A9%D9%87" title="مدل شبکه - persiano" lang="fa" hreflang="fa" data-title="مدل شبکه" data-language-autonym="فارسی" data-language-local-name="persiano" class="interlanguage-link-target"><span>فارسی</span></a></li><li class="interlanguage-link interwiki-fr mw-list-item"><a href="https://fr.wikipedia.org/wiki/Base_de_donn%C3%A9es_r%C3%A9seau" title="Base de données réseau - francese" lang="fr" hreflang="fr" data-title="Base de données réseau" data-language-autonym="Français" data-language-local-name="francese" class="interlanguage-link-target"><span>Français</span></a></li><li class="interlanguage-link interwiki-he mw-list-item"><a href="https://he.wikipedia.org/wiki/%D7%9E%D7%A1%D7%93_%D7%A0%D7%AA%D7%95%D7%A0%D7%99%D7%9D_%D7%A8%D7%A9%D7%AA%D7%99" title="מסד נתונים רשתי - ebraico" lang="he" hreflang="he" data-title="מסד נתונים רשתי" data-language-autonym="עברית" data-language-local-name="ebraico" class="interlanguage-link-target"><span>עברית</span></a></li><li class="interlanguage-link interwiki-hr mw-list-item"><a href="https://hr.wikipedia.org/wiki/Mre%C5%BEni_model" title="Mrežni model - croato" lang="hr" hreflang="hr" data-title="Mrežni model" data-language-autonym="Hrvatski" data-language-local-name="croato" class="interlanguage-link-target"><span>Hrvatski</span></a></li><li class="interlanguage-link interwiki-hu mw-list-item"><a href="https://hu.wikipedia.org/wiki/H%C3%A1l%C3%B3s_adatmodell" title="Hálós adatmodell - ungherese" lang="hu" hreflang="hu" data-title="Hálós adatmodell" data-language-autonym="Magyar" data-language-local-name="ungherese" class="interlanguage-link-target"><span>Magyar</span></a></li><li class="interlanguage-link interwiki-ia mw-list-item"><a href="https://ia.wikipedia.org/wiki/Base_de_datos_reticular" title="Base de datos reticular - interlingua" lang="ia" hreflang="ia" data-title="Base de datos reticular" data-language-autonym="Interlingua" data-language-local-name="interlingua" class="interlanguage-link-target"><span>Interlingua</span></a></li><li class="interlanguage-link interwiki-id mw-list-item"><a href="https://id.wikipedia.org/wiki/Model_jaringan" title="Model jaringan - indonesiano" lang="id" hreflang="id" data-title="Model jaringan" data-language-autonym="Bahasa Indonesia" data-language-local-name="indonesiano" class="interlanguage-link-target"><span>Bahasa Indonesia</span></a></li><li class="interlanguage-link interwiki-ja mw-list-item"><a href="https://ja.wikipedia.org/wiki/%E3%83%8D%E3%83%83%E3%83%88%E3%83%AF%E3%83%BC%E3%82%AF%E5%9E%8B%E3%83%87%E3%83%BC%E3%82%BF%E3%83%A2%E3%83%87%E3%83%AB" title="ネットワーク型データモデル - giapponese" lang="ja" hreflang="ja" data-title="ネットワーク型データモデル" data-language-autonym="日本語" data-language-local-name="giapponese" class="interlanguage-link-target"><span>日本語</span></a></li><li class="interlanguage-link interwiki-kk mw-list-item"><a href="https://kk.wikipedia.org/wiki/%D0%9C%D3%99%D0%BB%D1%96%D0%BC%D0%B5%D1%82%D1%82%D0%B5%D1%80%D0%B4%D1%96%D2%A3_%D0%B6%D0%B5%D0%BB%D1%96%D0%BB%D1%96%D0%BA_%D0%BC%D0%BE%D0%B4%D0%B5%D0%BB%D1%96" title="Мәліметтердің желілік моделі - kazako" lang="kk" hreflang="kk" data-title="Мәліметтердің желілік моделі" data-language-autonym="Қазақша" data-language-local-name="kazako" class="interlanguage-link-target"><span>Қазақша</span></a></li><li class="interlanguage-link interwiki-ko mw-list-item"><a href="https://ko.wikipedia.org/wiki/%EB%84%A4%ED%8A%B8%EC%9B%8C%ED%81%AC_%EB%AA%A8%EB%8D%B8" title="네트워크 모델 - coreano" lang="ko" hreflang="ko" data-title="네트워크 모델" data-language-autonym="한국어" data-language-local-name="coreano" class="interlanguage-link-target"><span>한국어</span></a></li><li class="interlanguage-link interwiki-lt mw-list-item"><a href="https://lt.wikipedia.org/wiki/Tinklin%C4%97_duomen%C5%B3_baz%C4%97" title="Tinklinė duomenų bazė - lituano" lang="lt" hreflang="lt" data-title="Tinklinė duomenų bazė" data-language-autonym="Lietuvių" data-language-local-name="lituano" class="interlanguage-link-target"><span>Lietuvių</span></a></li><li class="interlanguage-link interwiki-nl mw-list-item"><a href="https://nl.wikipedia.org/wiki/Netwerkdatabase" title="Netwerkdatabase - olandese" lang="nl" hreflang="nl" data-title="Netwerkdatabase" data-language-autonym="Nederlands" data-language-local-name="olandese" class="interlanguage-link-target"><span>Nederlands</span></a></li><li class="interlanguage-link interwiki-pl mw-list-item"><a href="https://pl.wikipedia.org/wiki/Sieciowa_baza_danych" title="Sieciowa baza danych - polacco" lang="pl" hreflang="pl" data-title="Sieciowa baza danych" data-language-autonym="Polski" data-language-local-name="polacco" class="interlanguage-link-target"><span>Polski</span></a></li><li class="interlanguage-link interwiki-ru mw-list-item"><a href="https://ru.wikipedia.org/wiki/%D0%A1%D0%B5%D1%82%D0%B5%D0%B2%D0%B0%D1%8F_%D0%BC%D0%BE%D0%B4%D0%B5%D0%BB%D1%8C_%D0%B4%D0%B0%D0%BD%D0%BD%D1%8B%D1%85" title="Сетевая модель данных - russo" lang="ru" hreflang="ru" data-title="Сетевая модель данных" data-language-autonym="Русский" data-language-local-name="russo" class="interlanguage-link-target"><span>Русский</span></a></li><li class="interlanguage-link interwiki-simple mw-list-item"><a href="https://simple.wikipedia.org/wiki/Network_model_(database)" title="Network model (database) - Simple English" lang="en-simple" hreflang="en-simple" data-title="Network model (database)" data-language-autonym="Simple English" data-language-local-name="Simple English" class="interlanguage-link-target"><span>Simple English</span></a></li><li class="interlanguage-link interwiki-ta mw-list-item"><a href="https://ta.wikipedia.org/wiki/%E0%AE%AA%E0%AE%BF%E0%AE%A3%E0%AF%88%E0%AE%AF_%E0%AE%AE%E0%AE%BE%E0%AE%A4%E0%AE%BF%E0%AE%B0%E0%AE%BF" title="பிணைய மாதிரி - tamil" lang="ta" hreflang="ta" data-title="பிணைய மாதிரி" data-language-autonym="தமிழ்" data-language-local-name="tamil" class="interlanguage-link-target"><span>தமிழ்</span></a></li><li class="interlanguage-link interwiki-tr mw-list-item"><a href="https://tr.wikipedia.org/wiki/A%C4%9F_modeli" title="Ağ modeli - turco" lang="tr" hreflang="tr" data-title="Ağ modeli" data-language-autonym="Türkçe" data-language-local-name="turco" class="interlanguage-link-target"><span>Türkçe</span></a></li><li class="interlanguage-link interwiki-uk mw-list-item"><a href="https://uk.wikipedia.org/wiki/%D0%9C%D0%B5%D1%80%D0%B5%D0%B6%D0%B5%D0%B2%D0%B0_%D0%BC%D0%BE%D0%B4%D0%B5%D0%BB%D1%8C_%D0%B4%D0%B0%D0%BD%D0%B8%D1%85" title="Мережева модель даних - ucraino" lang="uk" hreflang="uk" data-title="Мережева модель даних" data-language-autonym="Українська" data-language-local-name="ucraino" class="interlanguage-link-target"><span>Українська</span></a></li> </ul> <div class="after-portlet after-portlet-lang"><span class="wb-langlinks-edit wb-langlinks-link"><a href="https://www.wikidata.org/wiki/Special:EntityPage/Q1416406#sitelinks-wikipedia" title="Modifica collegamenti interlinguistici" class="wbc-editpage">Modifica collegamenti</a></span></div> </div> </div> </div> </header> <div class="vector-page-toolbar"> <div class="vector-page-toolbar-container"> <div id="left-navigation"> <nav aria-label="Namespace"> <div id="p-associated-pages" class="vector-menu vector-menu-tabs mw-portlet mw-portlet-associated-pages" > <div class="vector-menu-content"> <ul class="vector-menu-content-list"> <li id="ca-nstab-main" class="selected vector-tab-noicon mw-list-item"><a href="/wiki/Modello_reticolare" title="Vedi la voce [c]" accesskey="c"><span>Voce</span></a></li><li id="ca-talk" 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id="contentSub"><div id="mw-content-subtitle"></div></div> <div id="mw-content-text" class="mw-body-content"><div class="mw-content-ltr mw-parser-output" lang="it" dir="ltr"><style data-mw-deduplicate="TemplateStyles:r133964453">.mw-parser-output .avviso .mbox-text-div>div,.mw-parser-output .avviso .mbox-text-full-div>div{font-size:90%}.mw-parser-output .avviso .mbox-image{flex-basis:52px;flex-grow:0;flex-shrink:0}.mw-parser-output .avviso .mbox-text-full-div .hide-when-compact{display:block}</style><div style="" class="ambox metadata plainlinks avviso avviso-contenuto"> <div class="avviso-immagine mbox-image noprint"><span typeof="mw:File"><a href="/wiki/File:Question_book-4.svg" class="mw-file-description" title="Niente fonti!"><img alt="Niente fonti!" src="//upload.wikimedia.org/wikipedia/commons/thumb/6/64/Question_book-4.svg/45px-Question_book-4.svg.png" decoding="async" width="45" height="35" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/6/64/Question_book-4.svg/68px-Question_book-4.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/6/64/Question_book-4.svg/90px-Question_book-4.svg.png 2x" data-file-width="262" data-file-height="204" /></a></span></div> <div class="avviso-testo mbox-text"> <div class="mbox-text-div"><b>Questa voce o sezione  sull'argomento basi di dati <a href="/wiki/Wikipedia:Uso_delle_fonti" title="Wikipedia:Uso delle fonti">non cita le fonti necessarie</a> o quelle presenti sono insufficienti</b>. <div class="hide-when-compact"> <div class="noprint"><hr />Puoi <a class="external text" href="https://it.wikipedia.org/w/index.php?title=Modello_reticolare&action=edit">migliorare questa voce</a> aggiungendo citazioni da <a href="/wiki/Wikipedia:Fonti_attendibili" title="Wikipedia:Fonti attendibili">fonti attendibili</a> secondo le <a href="/wiki/Wikipedia:Uso_delle_fonti" title="Wikipedia:Uso delle fonti">linee guida sull'uso delle fonti</a>. </div> </div> </div> </div> </div> <figure class="mw-default-size" typeof="mw:File/Thumb"><a href="/wiki/File:Netzwerkdatenbankmodell.svg" class="mw-file-description"><img src="//upload.wikimedia.org/wikipedia/commons/thumb/1/1a/Netzwerkdatenbankmodell.svg/220px-Netzwerkdatenbankmodell.svg.png" decoding="async" width="220" height="165" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/1/1a/Netzwerkdatenbankmodell.svg/330px-Netzwerkdatenbankmodell.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/1/1a/Netzwerkdatenbankmodell.svg/440px-Netzwerkdatenbankmodell.svg.png 2x" data-file-width="240" data-file-height="180" /></a><figcaption>Modello reticolare di database</figcaption></figure> <p>In <a href="/wiki/Informatica" title="Informatica">informatica</a> il <b>modello reticolare</b> è una tipologia di implementazione di un <a href="/wiki/Database" class="mw-redirect" title="Database">database</a> ideato nel 1973 e perfezionato nel 1978 . La logica su cui si basa questo modello è basata su <a href="/wiki/Record_(database)" title="Record (database)">record</a> e <a href="/wiki/Puntatore_(programmazione)" title="Puntatore (programmazione)">puntatori</a>. Esso è stato recepito da un organismo di unificazione per cui ne esiste una versione <a href="/wiki/Standard_(informatica)" class="mw-redirect" title="Standard (informatica)">standard</a>, detta <a href="/w/index.php?title=CODASYL&action=edit&redlink=1" class="new" title="CODASYL (la pagina non esiste)">CODASYL</a>. Questo modello a differenza del <a href="/wiki/Modello_relazionale" title="Modello relazionale">modello relazionale</a> che si basa su gruppi di record, considera un record alla volta. Esso è molto vicino alla struttura fisica di memorizzazione dei record, infatti per poter "navigare" all'interno della <a href="/wiki/Base_di_dati" title="Base di dati">base di dati</a> si devono utilizzare i puntatori, proprio come avviene nella <a href="/wiki/Memoria_(informatica)" title="Memoria (informatica)">memoria</a> fisica di un <a href="/wiki/Computer" title="Computer">computer</a>. </p> <meta property="mw:PageProp/toc" /> <div class="mw-heading mw-heading2"><h2 id="Descrizione">Descrizione</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Modello_reticolare&veaction=edit&section=1" title="Modifica la sezione Descrizione" class="mw-editsection-visualeditor"><span>modifica</span></a><span class="mw-editsection-divider"> | </span><a href="/w/index.php?title=Modello_reticolare&action=edit&section=1" title="Edit section's source code: Descrizione"><span>modifica wikitesto</span></a><span class="mw-editsection-bracket">]</span></span></div> <div class="mw-heading mw-heading3"><h3 id="Strutture">Strutture</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Modello_reticolare&veaction=edit&section=2" title="Modifica la sezione Strutture" class="mw-editsection-visualeditor"><span>modifica</span></a><span class="mw-editsection-divider"> | </span><a href="/w/index.php?title=Modello_reticolare&action=edit&section=2" title="Edit section's source code: Strutture"><span>modifica wikitesto</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>La struttura è composta da uno schema che sarebbe il contenitore dei dati e di tutte le altre informazioni connesse. Il nome schema è stato dato in quanto una struttura può essere realmente disegnata graficamente come schema, con quadrati che rappresentano i record e frecce i <a href="/wiki/Puntatore_(programmazione)" title="Puntatore (programmazione)">puntatori</a>. Le strutture, come già detto prima, si basano su record e su <a href="/wiki/Puntatore_(programmazione)" title="Puntatore (programmazione)">puntatori</a> che li uniscono tra di loro; più precisamente parliamo di record come <i>file di record</i> in <a href="/wiki/COBOL" title="COBOL">COBOL</a>. Il comando <i>set</i> permette di creare <a href="/wiki/Puntatore_(programmazione)" title="Puntatore (programmazione)">puntatori</a> tra i vari record. Per quanto riguarda le strutture vi sono due definizioni importanti: </p> <ul><li><b>tipo di record</b>: è un tipo di dato composito, ed è costituito da un insieme di campi, ognuno dei quali è un tipo di dato semplice. Per ogni tipo di record vi deve essere definita direttamente o indirettamente la chiave: nel primo caso viene espressamente detto quali siano i campi (uno o più di uno) che la compongono, mentre nel secondo caso la chiave è dovuta ad uno o più puntatori provenienti da altri record.</li></ul> <ul><li><b>tipo di set</b>: è un legame logico tra due tipi di record distinti; tra un owner (proprietario) ed un member (membro) della relazione. La corrispondenza quindi che si può andare a creare è del tipo 1:n.</li></ul> <p>Quando andiamo ad istanziare un <i>tipo di record</i> andiamo a creare un <i>record</i>, ed allo stesso modo l'istanziazione di un <i>tipo di set</i> porta a creare un <i>set</i>. </p><p>Nelle strutture l'unico vincolo di integrità che si può andare a creare è l'obbligatorietà della partecipazione delle occorrenze tra tipi di set o meno. </p> <div class="mw-heading mw-heading3"><h3 id="DDL">DDL</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Modello_reticolare&veaction=edit&section=3" title="Modifica la sezione DDL" class="mw-editsection-visualeditor"><span>modifica</span></a><span class="mw-editsection-divider"> | </span><a href="/w/index.php?title=Modello_reticolare&action=edit&section=3" title="Edit section's source code: DDL"><span>modifica wikitesto</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>I DDL sono i comandi del <a href="/wiki/Data_Definition_Language" title="Data Definition Language">Data Definition Language</a> ovvero i comandi per poter costruire una <a href="/wiki/Base_di_dati" title="Base di dati">base di dati</a>. Nel modello reticolare i DDL sono i seguenti: </p> <ul><li>dichiarazione di schema;</li> <li>dichiarazione di record;</li> <li>criterio di memorizzazione;</li> <li>dichiarazione di campo;</li> <li>tipo semplice;</li> <li>dichiarazione di set;</li> <li>opzione di inserimento;</li> <li>opzione di ritenzione;</li> <li>opzione di ordinamento.</li></ul> <div class="mw-heading mw-heading3"><h3 id="DML">DML</h3><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Modello_reticolare&veaction=edit&section=4" title="Modifica la sezione DML" class="mw-editsection-visualeditor"><span>modifica</span></a><span class="mw-editsection-divider"> | </span><a href="/w/index.php?title=Modello_reticolare&action=edit&section=4" title="Edit section's source code: DML"><span>modifica wikitesto</span></a><span class="mw-editsection-bracket">]</span></span></div> <p>I DML sono i comandi del <a href="/wiki/Data_Manipulation_Language" class="mw-redirect" title="Data Manipulation Language">Data Manipulation Language</a> ovvero i comandi per effettuare modifiche sulla <a href="/wiki/Base_di_dati" title="Base di dati">base di dati</a>. Ricordando che la "navigazione" della <a href="/wiki/Base_di_dati" title="Base di dati">base di dati</a> viene fatta seguendo i puntatori, essa viene fatta sfruttando un linguaggio ospite che sia dotato di comandi DML per una base di dati reticolare (es. <a href="/wiki/COBOL" title="COBOL">COBOL</a>). Dovendo "navigare" la base di dati vi è la necessità di utilizzare dei cicli per compiere le operazioni desiderate, ed è fondamentale avere sempre un riferimento al "record corrente", ovvero il record a cui stiamo puntando in ogni momento. Le operazioni che possono essere eseguite sono: </p> <ul><li><b>ricerca</b>: per ricercare dati all'interno della struttura si deve utilizzare il comando <i>find</i>. Per poter estrarre dati dallo schema e passarli al programma si utilizza l'istruzione <i>get</i> che copia il contenuto del record corrente nel buffer del programma che sta interagendo con la base di dati.</li> <li><b>aggiornamento</b>: gli aggiornamenti possono essere fatti un record alla volta. Per inserire un nuovo record si utilizza il comando <i>store</i>, per la modifica di un record già esistente si utilizza il comando <i>modify</i>, mentre per la cancellazione <i>erase</i>.</li></ul> <div class="mw-heading mw-heading2"><h2 id="Altri_progetti">Altri progetti</h2><span class="mw-editsection"><span class="mw-editsection-bracket">[</span><a href="/w/index.php?title=Modello_reticolare&veaction=edit&section=5" title="Modifica la sezione Altri progetti" class="mw-editsection-visualeditor"><span>modifica</span></a><span class="mw-editsection-divider"> | </span><a href="/w/index.php?title=Modello_reticolare&action=edit&section=5" title="Edit section's source code: Altri progetti"><span>modifica wikitesto</span></a><span class="mw-editsection-bracket">]</span></span></div> <div id="interProject" class="toccolours" style="display: none; clear: both; margin-top: 2em"><p id="sisterProjects" style="background-color: #efefef; color: black; font-weight: bold; margin: 0"><span>Altri progetti</span></p><ul title="Collegamenti verso gli altri progetti Wikimedia"> <li class="" title=""><span class="plainlinks" title="commons:Category:Network models"><a class="external text" href="https://commons.wikimedia.org/wiki/Category:Network_models?uselang=it">Wikimedia Commons</a></span></li></ul></div> <ul><li><span typeof="mw:File"><a href="https://commons.wikimedia.org/wiki/?uselang=it" title="Collabora a Wikimedia Commons"><img alt="Collabora a Wikimedia Commons" src="//upload.wikimedia.org/wikipedia/commons/thumb/4/4a/Commons-logo.svg/18px-Commons-logo.svg.png" decoding="async" width="18" height="24" class="mw-file-element" srcset="//upload.wikimedia.org/wikipedia/commons/thumb/4/4a/Commons-logo.svg/27px-Commons-logo.svg.png 1.5x, //upload.wikimedia.org/wikipedia/commons/thumb/4/4a/Commons-logo.svg/36px-Commons-logo.svg.png 2x" data-file-width="1024" data-file-height="1376" /></a></span> <span class="plainlinks"><a class="external text" href="https://commons.wikimedia.org/wiki/?uselang=it">Wikimedia Commons</a></span> contiene immagini o altri file sul <b><span class="plainlinks"><a class="external text" href="https://commons.wikimedia.org/wiki/Category:Network_models?uselang=it">modello reticolare</a></span></b></li></ul> <div class="noprint" style="width:100%; 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