Revision 1034116 of IDBIndex.multiEntry

<p>{{ APIRef("IndexedDB") }}</p>

<div>
<p>The <strong><code>multiEntry</code></strong> property of the {{domxref("IDBIndex")}} interface&nbsp;returns a boolean value that affects how the index behaves when the result of evaluating the index's key path yields an array.</p>

<p>This is decided when the index is created, using the {{domxref("IDBObjectStore.createIndex")}} method. This method takes an optional options parameter shoe <code style="font-style: normal;">multiEntry</code> property is set to&nbsp;<code style="font-style: normal;">true</code>/<code style="font-style: normal;">false</code>.</p>

<p>{{AvailableInWorkers}}</p>
</div>

<h2 id="Syntax">Syntax</h2>

<pre class="brush: js" style="font-size: 14px;">
var myIndex = objectStore.index('index');
console.log(myIndex.multiEntry);</pre>

<h3 id="Value">Value</h3>

<p>A {{domxref("Boolean")}}:</p>

<table class="standard-table">
 <tbody>
  <tr>
   <th>Value</th>
   <th>Effect</th>
  </tr>
  <tr>
   <td>true</td>
   <td>There is one record in the index for each item in an array of keys.</td>
  </tr>
  <tr>
   <td>false</td>
   <td>There is one record for each key that is an array.</td>
  </tr>
 </tbody>
</table>

<h2 id="Example">Example</h2>

<p>In the following example we open a transaction and an object store, then get the index&nbsp;<code>lName</code>&nbsp;from a simple contacts database. We then open a basic cursor on the index using {{domxref("IDBIndex.openCursor")}}&nbsp;— this works the same as opening a cursor directly on an&nbsp;<code>ObjectStore</code>&nbsp;using {{domxref("IDBObjectStore.openCursor")}} except that the returned records are sorted based on the index, not the primary key.</p>

<p>The multi-entry status of the index is logged to the console: it should be returned as&nbsp;<code>false</code>.</p>

<p>Finally, we iterate through each record, and insert the data into an HTML table. For a complete working example, see our&nbsp;<a href="https://github.com/mdn/IDBIndex-example">IDBIndex-example demo repo</a>&nbsp;(<a href="https://mdn.github.io/IDBIndex-example/">View the example live</a>.)</p>

<pre style="font-size: 14px;">
function displayDataByIndex() {
  tableEntry.innerHTML = '';
  var transaction = db.transaction(['contactsList'], 'readonly');
  var objectStore = transaction.objectStore('contactsList');

  var myIndex = objectStore.index('lName'); 
  console.log(myIndex.multiEntry);

  myIndex.openCursor().onsuccess = function(event) {
    var cursor = event.target.result;
    if(cursor) {
      var tableRow = document.createElement('tr');
      tableRow.innerHTML =   '&lt;td&gt;' + cursor.value.id + '&lt;/td&gt;'
                           + '&lt;td&gt;' + cursor.value.lName + '&lt;/td&gt;'
                           + '&lt;td&gt;' + cursor.value.fName + '&lt;/td&gt;'
                           + '&lt;td&gt;' + cursor.value.jTitle + '&lt;/td&gt;'
                           + '&lt;td&gt;' + cursor.value.company + '&lt;/td&gt;'
                           + '&lt;td&gt;' + cursor.value.eMail + '&lt;/td&gt;'
                           + '&lt;td&gt;' + cursor.value.phone + '&lt;/td&gt;'
                           + '&lt;td&gt;' + cursor.value.age + '&lt;/td&gt;';
      tableEntry.appendChild(tableRow);  

      cursor.continue();
    } else {
      console.log('Entries all displayed.');    
    }
  };
};</pre>

<h2 id="Specification">Specification</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', '#widl-IDBIndex-multiEntry', 'multiEntry')}}</td>
   <td>{{Spec2('IndexedDB')}}</td>
   <td>&nbsp;</td>
  </tr>
 </tbody>
</table>

<h2 id="Browser_compatibility" name="Browser_compatibility">Browser compatibility</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>
  <tr>
   <td>Available in workers</td>
   <td>{{CompatVersionUnknown}}</td>
   <td>{{CompatGeckoMobile("37.0")}}</td>
   <td>{{CompatUnknown}}</td>
   <td>{{CompatVersionUnknown}}</td>
   <td>{{CompatUnknown}}</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>8</td>
  </tr>
  <tr>
   <td>Available in workers</td>
   <td>{{CompatVersionUnknown}}</td>
   <td>{{CompatGeckoMobile("37.0")}}</td>
   <td>{{CompatVersionUnknown}}</td>
   <td>{{CompatUnknown}}</td>
   <td>{{CompatVersionUnknown}}</td>
   <td>{{CompatUnknown}}</td>
  </tr>
 </tbody>
</table>
</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="https://mdn.github.io/to-do-notifications/">view example live</a>.)</li>
</ul>