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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/idbobjectstore/opencursor/index.html | |
parent | 8b66d724f7caf0157093fb09cfec8fbd0c6ad50a (diff) | |
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diff --git a/files/zh-cn/web/api/idbobjectstore/opencursor/index.html b/files/zh-cn/web/api/idbobjectstore/opencursor/index.html new file mode 100644 index 0000000000..764582ad9a --- /dev/null +++ b/files/zh-cn/web/api/idbobjectstore/opencursor/index.html @@ -0,0 +1,171 @@ +--- +title: IDBObjectStore.openCursor +slug: Web/API/IDBObjectStore/openCursor +translation_of: Web/API/IDBObjectStore/openCursor +--- +<p>{{ APIRef("IDBObjectStore") }}</p> + +<div> +<p>{{domxref("IDBObjectStore")}} 的 <code>openCursor()</code> 方法 返回一个{{domxref("IDBRequest")}} 对象,并在一个单独的线程中,返回一个新的 {{domxref("IDBCursorWithValue")}} 对象。此方法目的是用一个游标来遍历一个对象存储空间。</p> +</div> + +<p>若要确认此操作是否成功完成,请监听结果的 <code>success</code> 事件。</p> + +<p>{{AvailableInWorkers}}</p> + +<h2 id="语法">语法</h2> + +<pre class="brush: js">var request = ObjectStore.openCursor(query, direction);</pre> + +<h3 id="参数">参数</h3> + +<dl> + <dt>query {{optional_inline}}</dt> + <dd>要查询的键或者 {{domxref("IDBKeyRange")}} 。如果传一个有效的键,则会默认为只包含此键的范围。如果此参数不传值,则默认为一个选择了该对象存储空间全部记录的键范围。</dd> + <dt>direction {{optional_inline}}</dt> + <dd>一个 {{domxref("IDBCursorDirection")}} 来告诉游标要移动的方向。有效的值有 <code>"next"</code> 、<code>"nextunique"</code> 、<code>"prev"</code> 和 <code>"prevunique"</code>。默认值是 <code>"next"</code>。</dd> +</dl> + +<h3 id="返回">返回</h3> + +<p>一个 {{domxref("IDBRequest")}} 对象,在此对象上触发与此操作相关的后续事件。</p> + +<h3 id="异常">异常</h3> + +<p>此方法可能引起以下类型之一的 {{domxref("DOMException")}} :</p> + +<table class="standard-table"> + <thead> + <tr> + <th scope="col">异常</th> + <th scope="col">描述</th> + </tr> + </thead> + <tbody> + <tr> + <td><code>InvalidStateError</code></td> + <td>此 {{domxref("IDBObjectStore")}} 或{{domxref("IDBIndex")}} 已被删除。</td> + </tr> + <tr> + <td><code>TransactionInactiveError</code></td> + <td>此 {{domxref("IDBObjectStore")}} 的事务处于非活动状态。</td> + </tr> + <tr> + <td><code><span style="line-height: normal;">DataError</span></code></td> + <td>指定的键或键范围无效。</td> + </tr> + </tbody> +</table> + +<h2 id="例子">例子</h2> + +<p>在下面这个简单的片段中,我们创建一个事务,检索一个对象存储空间,然后用一个游标去遍历该对象存储空间的所有记录:</p> + +<pre class="brush: js">var transaction = db.transaction("name", "readonly"); +var objectStore = transaction.objectStore("name"); +var request = objectStore.openCursor(); +request.onsuccess = function(event) { + var cursor = event.target.result; + if(cursor) { + // cursor.value 包含正在被遍历的当前记录 + // 这里你可以对 result 做些什么 + cursor.continue(); + } else { + // 没有更多 results + } +}; + +</pre> + +<h2 id="规范">规范 </h2> + +<dl> +</dl> + +<table class="standard-table"> + <thead> + <tr> + <th scope="col">Specification</th> + <th scope="col">Status</th> + <th scope="col">Comment</th> + </tr> + </thead> + <tbody> + <tr> + <td>{{SpecName('IndexedDB', '#widl-IDBIndex-openCursor-IDBRequest-any-range-IDBCursorDirection-direction', 'openCursor()')}}</td> + <td>{{Spec2('IndexedDB')}}</td> + <td> </td> + </tr> + <tr> + <td>{{SpecName("IndexedDB 2", "#dom-idbobjectstore-opencursor", "openCursor()")}}</td> + <td>{{Spec2("IndexedDB 2")}}</td> + <td> </td> + </tr> + </tbody> +</table> + +<h2 id="浏览器兼容性">浏览器兼容性</h2> + +<div>{{CompatibilityTable}}</div> + +<div id="compat-desktop"> +<table class="compat-table"> + <tbody> + <tr> + <th>Feature</th> + <th>Chrome</th> + <th>Firefox (Gecko)</th> + <th>Internet Explorer</th> + <th>Opera</th> + <th>Safari (WebKit)</th> + </tr> + <tr> + <td>Basic support</td> + <td>23{{property_prefix("webkit")}}<br> + 24</td> + <td>10 {{property_prefix("moz")}}<br> + {{CompatGeckoDesktop("16.0")}}</td> + <td>10, partial</td> + <td>15</td> + <td>7.1</td> + </tr> + </tbody> +</table> +</div> + +<div id="compat-mobile"> +<table class="compat-table"> + <tbody> + <tr> + <th>Feature</th> + <th>Android</th> + <th>Firefox Mobile (Gecko)</th> + <th>Firefox OS</th> + <th>IE Phone</th> + <th>Opera Mobile</th> + <th>Safari Mobile</th> + </tr> + <tr> + <td>Basic support</td> + <td>4.4</td> + <td>{{CompatGeckoMobile("22.0")}}</td> + <td>1.0.1</td> + <td>10</td> + <td>22</td> + <td>{{CompatNo}}</td> + </tr> + </tbody> +</table> +</div> + +<h2 id="另请参阅">另请参阅</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> |