IDBIndex: multiEntry property
Note: This feature is available in Web Workers.
The multiEntry
read-only 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 whose multiEntry
property is set to true
/false
.
Value
A boolean value:
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. |
Examples
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 IndexedDB-examples demo repo (View the example live).
function displayDataByIndex() {
tableEntry.textContent = "";
const transaction = db.transaction(["contactsList"], "readonly");
const objectStore = transaction.objectStore("contactsList");
const myIndex = objectStore.index("lName");
console.log(myIndex.multiEntry);
myIndex.openCursor().onsuccess = (event) => {
const cursor = event.target.result;
if (cursor) {
const tableRow = document.createElement("tr");
for (const cell of [
cursor.value.id,
cursor.value.lName,
cursor.value.fName,
cursor.value.jTitle,
cursor.value.company,
cursor.value.eMail,
cursor.value.phone,
cursor.value.age,
]) {
const tableCell = document.createElement("td");
tableCell.textContent = cell;
tableRow.appendChild(tableCell);
}
tableEntry.appendChild(tableRow);
cursor.continue();
} else {
console.log("Entries all displayed.");
}
};
}
Specifications
Specification |
---|
Indexed Database API 3.0 # dom-idbindex-multientry |
Browser compatibility
BCD tables only load in the browser
See also
- Using IndexedDB
- Starting transactions:
IDBDatabase
- Using transactions:
IDBTransaction
- Setting a range of keys:
IDBKeyRange
- Retrieving and making changes to your data:
IDBObjectStore
- Using cursors:
IDBCursor
- Reference example: To-do Notifications (View the example live).