IDBIndex.multiEntry

The multiEntry property of the IDBIndex interface returns a boolean value that affects how the index behaves when the result of evaluating the index's key path yields an array.

This is decided when the index is created, using the IDBObjectStore.createIndex method. This method takes an optional options parameter shoe multiEntry property is set to true/false.

Note: This feature is available in Web Workers.

Syntax

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

Value

A Boolean:

Value Effect
true There is one record in the index for each item in an array of keys.
false There is one record for each key that is an array.

Example

In the following example we open a transaction and an object store, then get the index lName from a simple contacts database. We then open a basic cursor on the index using IDBIndex.openCursor — this works the same as opening a cursor directly on an ObjectStore using IDBObjectStore.openCursor except that the returned records are sorted based on the index, not the primary key.

The multi-entry status of the index is logged to the console: it should be returned as false.

Finally, we iterate through each record, and insert the data into an HTML table. For a complete working example, see our IDBIndex-example demo repo (View the example live.)

JavaScript
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 =   '<td>' + cursor.value.id + '</td>'
                           + '<td>' + cursor.value.lName + '</td>'
                           + '<td>' + cursor.value.fName + '</td>'
                           + '<td>' + cursor.value.jTitle + '</td>'
                           + '<td>' + cursor.value.company + '</td>'
                           + '<td>' + cursor.value.eMail + '</td>'
                           + '<td>' + cursor.value.phone + '</td>'
                           + '<td>' + cursor.value.age + '</td>';
      tableEntry.appendChild(tableRow);  

      cursor.continue();
    } else {
      console.log('Entries all displayed.');    
    }
  };
};

Specification

Specification Status Comment
Indexed Database API
The definition of 'multiEntry' in that specification.
Editor's Draft  

Browser compatibility

Feature Chrome Firefox (Gecko) Internet Explorer Opera Safari (WebKit)
Basic support 23webkit
24
10 moz
16.0 (16.0)
10, partial 15 7.1
Available in workers (Yes) 37.0 (37.0) ? (Yes) ?
Feature Android Firefox Mobile (Gecko) Firefox OS IE Phone Opera Mobile Safari Mobile
Basic support 4.4 22.0 (22.0) 1.0.1 10 22 8
Available in workers (Yes) 37.0 (37.0) (Yes) ? (Yes) ?

See also

License

© 2016 Mozilla Contributors
Licensed under the Creative Commons Attribution-ShareAlike License v2.5 or later.
https://developer.mozilla.org/en-us/docs/web/api/idbindex/multientry

API Database IDBIndex IndexedDB multiEntry Property Reference Storage storage