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author | Peter Bengtsson <mail@peterbe.com> | 2020-12-08 14:40:17 -0500 |
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committer | Peter Bengtsson <mail@peterbe.com> | 2020-12-08 14:40:17 -0500 |
commit | 33058f2b292b3a581333bdfb21b8f671898c5060 (patch) | |
tree | 51c3e392513ec574331b2d3f85c394445ea803c6 /files/zh-cn/web/api/idbopendbrequest | |
parent | 8b66d724f7caf0157093fb09cfec8fbd0c6ad50a (diff) | |
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diff --git a/files/zh-cn/web/api/idbopendbrequest/index.html b/files/zh-cn/web/api/idbopendbrequest/index.html new file mode 100644 index 0000000000..5a086251b4 --- /dev/null +++ b/files/zh-cn/web/api/idbopendbrequest/index.html @@ -0,0 +1,125 @@ +--- +title: IDBOpenDBRequest +slug: Web/API/IDBOpenDBRequest +translation_of: Web/API/IDBOpenDBRequest +--- +<p>{{APIRef("IndexedDB")}}</p> + +<div> +<p>IndexedDB API 的 <strong><code>IDBOpenDBRequest</code></strong> 接口提供了访问打开或删除数据库的请求的结果(通过调用 {{domxref("IDBFactory.open")}} and {{domxref("IDBFactory.deleteDatabase")}}),途径就是使用特殊的事件处理器属性。</p> +</div> + +<p>{{AvailableInWorkers}}</p> + +<p>{{InheritanceDiagram}}</p> + +<h2 id="Properties">Properties</h2> + +<p><em>Also inherits methods from its parents {{domxref("IDBRequest")}} and {{domxref("EventTarget")}}</em>.</p> + +<h3 id="Events">Events</h3> + +<dl> + <dt>{{domxref("IDBOpenDBRequest.onblocked")}}</dt> + <dd>The event handler for the blocked event. This event is triggered when the <code>upgradeneeded</code> event should be triggered because of a version change but the database is still in use (i.e. not closed) somewhere, even after the <code>versionchange</code> event was sent.</dd> + <dt>{{domxref("IDBOpenDBRequest.onupgradeneeded")}}</dt> + <dd><code>upgradeneeded</code> 事件的事件处理器,会在当一个数据库的版本比已经存在的版本还高的时候触发。</dd> + <dt> + <h2 id="Methods">Methods</h2> + + <p><em>No methods, but inherits methods from its parents {{domxref("IDBRequest")}} and {{domxref("EventTarget")}}.</em></p> + </dt> +</dl> + +<h2 id="Example">Example</h2> + +<p>In the following example you can see the onupgradeneeded handler being used to update the database structure if a database with a higher version number is loaded. For a full working example, see our <a class="external" href="https://github.com/mdn/to-do-notifications/tree/gh-pages">To-do Notifications</a> app (<a class="external" href="http://mdn.github.io/to-do-notifications/">view example live</a>.)</p> + +<pre class="brush: js; highlight:[16,28,29,31,32,33,34,35,36]">var db; + +// Let us open our database +var DBOpenRequest = window.indexedDB.open("toDoList", 4); + +// these event handlers act on the database being opened. +DBOpenRequest.onerror = function(event) { + note.innerHTML += '<li>Error loading database.</li>'; +}; + +DBOpenRequest.onsuccess = function(event) { + note.innerHTML += '<li>Database initialised.</li>'; + + // store the result of opening the database in the db + // variable. This is used a lot below + db = DBOpenRequest.result; + + // Run the displayData() function to populate the task + // listwith all the to-do list data already in the IDB + displayData(); +}; + +// This event handles the event whereby a new version of +// the database needs to be created Either one has not +// been created before, or a new version number has been +// submitted via the window.indexedDB.open line above +// it is only implemented in recent browsers +DBOpenRequest.onupgradeneeded = function(event) { + var db = this.result; + + db.onerror = function(event) { + note.innerHTML += '<li>Error loading database.</li>'; + }; + + // Create an objectStore for this database + var objectStore = db.createObjectStore("toDoList", { keyPath: "taskTitle" }); + + // define what data items the objectStore will contain + + objectStore.createIndex("hours", "hours", { unique: false }); + objectStore.createIndex("minutes", "minutes", { unique: false }); + objectStore.createIndex("day", "day", { unique: false }); + objectStore.createIndex("month", "month", { unique: false }); + objectStore.createIndex("year", "year", { unique: false }); + objectStore.createIndex("notified", "notified", { unique: false }); +};</pre> + +<h2 id="Specifications">Specifications</h2> + +<table class="standard-table"> + <tbody> + <tr> + <th scope="col">Specification</th> + <th scope="col">Status</th> + <th scope="col">Comment</th> + </tr> + <tr> + <td>{{SpecName('IndexedDB', '#idl-def-IDBOpenDBRequest', 'IDBOpenDBRequest')}}</td> + <td>{{Spec2('IndexedDB')}}</td> + <td>Initial definition</td> + </tr> + <tr> + <td>{{SpecName("IndexedDB 2", "#idbopendbrequest", "IDBOpenDBRequest")}}</td> + <td>{{Spec2("IndexedDB 2")}}</td> + <td> </td> + </tr> + </tbody> +</table> + +<h2 id="Browser_compatibility">Browser compatibility</h2> + +<div> + + +<p>{{Compat("api.IDBOpenDBRequest")}}</p> +</div> + +<h2 id="See_also">See also</h2> + +<ul> + <li><a href="/en-US/docs/Web/API/IndexedDB_API/Using_IndexedDB">Using IndexedDB</a></li> + <li>Starting transactions: {{domxref("IDBDatabase")}}</li> + <li>Using transactions: {{domxref("IDBTransaction")}}</li> + <li>Setting a range of keys: {{domxref("IDBKeyRange")}}</li> + <li>Retrieving and making changes to your data: {{domxref("IDBObjectStore")}}</li> + <li>Using cursors: {{domxref("IDBCursor")}}</li> + <li>Reference example: <a class="external" href="https://github.com/mdn/to-do-notifications/tree/gh-pages">To-do Notifications</a> (<a class="external" href="http://mdn.github.io/to-do-notifications/">view example live</a>.)</li> +</ul> |