Indexed Database

In HTML5, an indexed database is a local storage used to store and manipulate key-value format data in a client. You can implement effective searches using an index, which is a specialized persistent key-value storage containing entries from the database based on specific property values.

The main features of the Indexed Database API include the following:

  • Creating a database

    Use the IndexedDB.open() method to create a database. In a database (in mobile, wearable, and TV applications), at least 1 object store (in mobile, wearable, and TV applications) must be present.

  • Creating an object store

    Object store is the basic storage mechanism of indexed database storage data.

    You can create an object store using the createObjectStore() method. The object store contains a list of records for storing data, and a key-value list sorted according to the key in an ascending order.

  • Managing data

    You can save and access data in the object store.

    The stored data creates a key, assigned to a keypath, which in turn creates a value as a JSON object.

    Note

    Tizen supports the READ_ONLY, READ_WRITE, and VERSION_CHANGE transactions (in mobile, wearable, and TV applications) with the unsigned short type.

  • Creating an index

    In the object store, you can use the createIndex() method to generate an index. You can search for and retrieve records stored in the index (in mobile, wearable, and TV applications) using other properties than the key, as the key is not always unique. You can also retrieve records containing arrays as keys.

Create a database

Creating and deleting a database is a useful data management skill, follow these steps to create and delete a database:

  1. Use the window.webkitIndexedDB.open() method to generate a database named TizenIndexedDB in order to create an object store for storage:

    <script>
    if (!window.webkitIndexedDB) {
        window.alert('Does not support IndexedDB');
    } else {
        var tizenDB = {};
        var request = window.webkitIndexedDB.open('TizenIndexedDB');

        request.onsuccess = function(e) {};
        request.onerror = function(e) {/* Error handling */};
    }
</script>

    Check whether an indexed database is supported in the window object. If the database is generated properly, the onsuccess event handler is called.

    Note

    The name of the database can be any string type, including an empty string. To change the version of the database, use the VERSION_CHANGE transaction.

  2. Delete the generated database using the window.webkitIndexedDB.deleteDatabase() method:

    <script>
    window.webkitIndexedDB.deleteDatabase('TizenIndexedDB');
</script>

Source Code

For the complete source code related to this use case, see the following file:

Create an object store

An object store can derive keys from the following sources:

  • Key generator (in mobile, wearable, and TV applications)

    Generates an increasing number every time a key is needed.

  • Key path (in mobile, wearable, and TV applications)

    Key is derived through a key path.

  • Value (in mobile, wearable, and TV applications)

    Key is specified when a value is stored in the object store.

Creating and deleting an object store is a useful data management skill:

  1. To generate an object store for data storage, use the createObjectStore() method:

    <script>
    var tizenDB = {}
    var request = window.webkitIndexedDB.open('TizenIndexedDB');
    request.onupgradeneeded = function(e) {
        tizenDB.db = event.target.result;
        try {
            var objStore = tizenDB.db.createObjectStore('tizenStore', {keyPath: 'key'});
        }
    };
</script>

    The name and key path of an independent object are defined in the object store. The keyPath property makes the object store unique and must contain the key attribute to store data in the object store.

  2. To delete the object store, use the deleteObjectStore() method:

    <script>
    window.webkitIndexedDB.deleteObjectStore('tizenStore');
</script>

Source code

For the complete source code related to this use case, see the following file:

Manage data

Saving, accessing, and deleting data in an object store is a useful data management skill, follow these steps to save, access, and delete a data:

  1. Access the object store using the readwrite transaction and save data using the put() method:

    <script>
    objStore.transaction.oncomplete = function(e) {
        var trans = tizenDB.db.transaction('tizenStore', 'readwrite');
        var tizenStore = trans.objectStore('tizenStore');
        var data = {
            'key': new Date().getTime(),
            'text': 'Tizen-' + Math.random()
        };

        var request = tizenStore.put(data);
        request.onsuccess = function(e) {
            tizenDB.db.objectStoreId = request.result;
            console.log(request.result);
        };
    };
</script>

  2. Request data in the tizenStore object store by calling data relevant to the key value in the storage with the get() method:

    <script>
    var request = tizenStore.put(data);
    request.onsuccess = function(e) {
        tizenDB.db.objectStoreId = request.result;
        var data = tizenStore.get(tizenDB.db.objectStoreId);
    };
</script>

  3. Delete the data in the object store using the delete() method:

    <script>
    var request = tizenStore.put(data);
    request.onsuccess = function(e) {
        tizenDB.db.objectStoreId = request.result;
        var data = tizenStore.delete(tizenDB.db.objectStoreId);
        data.onsuccess = function(e) {
            console.log(data);
        };
    };
</script>

Source code

For the complete source code related to this use case, see the following file:

Create an index

Creating, accessing, and deleting an index is a useful data management skill, follow these steps to create, access, and delete an index:

  1. Create an index named tizen01 to search for stored data in records based on its property (text):

    <script>
    var objStore = tizenDB.db.createObjectStore('tizenStore', {keyPath: 'key'});
    tizenDB.index = objStore.createIndex('tizen01', 'text');

  2. Access the index using the objStore.index() method:

        var dbIndex = objStore.index('tizen01');

  3. Delete the index using the objStore.deleteIndex() method:

        tizenDB.index = objStore.deleteIndex('tizen01');
</script>

Source code

For the complete source code related to this use case, see the following file:

  • Dependencies
    • Tizen 2.4 and Higher for Mobile
    • Tizen 2.3.1 and Higher for Wearable
    • Tizen 3.0 and Higher for TV
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