Question

I’ve been playing around with indexed_db a bit, and it looks fairly impressive thus far.

I’m having a problem selecting a single record however, and the only way that I could get it to work is to select the whole “table” and process it until I encounter the key that I require. (objectStore.openCursor()). I presume that index.getKey() can be used in some way, but I couldn’t find out how to make this work. The other thing I attempted was index.openCursor().

Could someone please post a working example of how to do this? (Select a single “record” by key).

Answer 1

Try something like this:

import 'dart:html';
import 'dart:indexed_db';


void main() {

  List data = [
               {"name":"Chris", "lang":"Dart"},
               {"name":"Tom", "lang": "Java"}
               ];

  OpenDBRequest request = window.indexedDB.open("MyDatabase", 1);

  // create the structure
  request.onUpgradeNeeded.first.then((d) {
    var db = request.result;
    var objectStore = db.createObjectStore("people", { "keyPath":"name" });

    // create an index
    objectStore.createIndex("name", "name", { "unique": false });

    // insert some data
    data.forEach((record) => objectStore.add(record));
  });  

  // query for item with the name="Chris"
  request.onSuccess.first.then((v) {
    var db = request.result;

    var objectStore = db.transaction("people","readwrite").objectStore("people");

    // query for the object where name = "Chris"
    var requestedObject = objectStore.getObject("Chris");

    requestedObject.onSuccess.first.then((val) {
      // we've retrieved the value, print out fields
      print(requestedObject.result["name"]); // Chris
      print(requestedObject.result["lang"]); // "Dart"
    });

  });


}

References:
I used this github code from todo MVC example, and these MDN docs to understand IndexedDB (and Dart SDK + Editor 17463)