From 33058f2b292b3a581333bdfb21b8f671898c5060 Mon Sep 17 00:00:00 2001 From: Peter Bengtsson Date: Tue, 8 Dec 2020 14:40:17 -0500 Subject: initial commit --- files/zh-cn/web/api/idbopendbrequest/index.html | 125 ++++++++++++++++++++++++ 1 file changed, 125 insertions(+) create mode 100644 files/zh-cn/web/api/idbopendbrequest/index.html (limited to 'files/zh-cn/web/api/idbopendbrequest') diff --git a/files/zh-cn/web/api/idbopendbrequest/index.html b/files/zh-cn/web/api/idbopendbrequest/index.html new file mode 100644 index 0000000000..5a086251b4 --- /dev/null +++ b/files/zh-cn/web/api/idbopendbrequest/index.html @@ -0,0 +1,125 @@ +--- +title: IDBOpenDBRequest +slug: Web/API/IDBOpenDBRequest +translation_of: Web/API/IDBOpenDBRequest +--- +

{{APIRef("IndexedDB")}}

+ +
+

IndexedDB API 的 IDBOpenDBRequest 接口提供了访问打开或删除数据库的请求的结果（通过调用 {{domxref("IDBFactory.open")}} and {{domxref("IDBFactory.deleteDatabase")}}），途径就是使用特殊的事件处理器属性。

+
+ +

{{AvailableInWorkers}}

+ +

{{InheritanceDiagram}}

+ +

Properties

+ +

Also inherits methods from its parents {{domxref("IDBRequest")}} and {{domxref("EventTarget")}}.

+ +

Events

+ +
+
{{domxref("IDBOpenDBRequest.onblocked")}}
+
The event handler for the blocked event. This event is triggered when the upgradeneeded event should be triggered because of a version change but the database is still in use (i.e. not closed) somewhere, even after the versionchange event was sent.
+
{{domxref("IDBOpenDBRequest.onupgradeneeded")}}
+
upgradeneeded 事件的事件处理器，会在当一个数据库的版本比已经存在的版本还高的时候触发。
+
+

Methods

+ +

No methods, but inherits methods from its parents {{domxref("IDBRequest")}} and {{domxref("EventTarget")}}.

+
+
+ +

Example

+ +

In the following example you can see the onupgradeneeded handler being used to update the database structure if a database with a higher version number is loaded. For a full working example, see our To-do Notifications app (view example live.)

+ +
var db;
+
+// Let us open our database
+var DBOpenRequest = window.indexedDB.open("toDoList", 4);
+
+// these event handlers act on the database being opened.
+DBOpenRequest.onerror = function(event) {
+  note.innerHTML += '<li>Error loading database.</li>';
+};
+
+DBOpenRequest.onsuccess = function(event) {
+  note.innerHTML += '<li>Database initialised.</li>';
+
+  // store the result of opening the database in the db
+  // variable. This is used a lot below
+  db = DBOpenRequest.result;
+
+  // Run the displayData() function to populate the task
+  // listwith all the to-do list data already in the IDB
+  displayData();
+};
+
+// This event handles the event whereby a new version of
+// the database needs to be created Either one has not
+// been created before, or a new version number has been
+// submitted via the window.indexedDB.open line above
+// it is only implemented in recent browsers
+DBOpenRequest.onupgradeneeded = function(event) {
+  var db = this.result;
+
+  db.onerror = function(event) {
+    note.innerHTML += '<li>Error loading database.</li>';
+  };
+
+  // Create an objectStore for this database
+  var objectStore = db.createObjectStore("toDoList", { keyPath: "taskTitle" });
+
+  // define what data items the objectStore will contain
+
+  objectStore.createIndex("hours", "hours", { unique: false });
+  objectStore.createIndex("minutes", "minutes", { unique: false });
+  objectStore.createIndex("day", "day", { unique: false });
+  objectStore.createIndex("month", "month", { unique: false });
+  objectStore.createIndex("year", "year", { unique: false });
+  objectStore.createIndex("notified", "notified", { unique: false });
+};
+ +

Specifications

+ + + + + + + + + + + + + + + + + + + +
SpecificationStatusComment
{{SpecName('IndexedDB', '#idl-def-IDBOpenDBRequest', 'IDBOpenDBRequest')}}{{Spec2('IndexedDB')}}Initial definition
{{SpecName("IndexedDB 2", "#idbopendbrequest", "IDBOpenDBRequest")}}{{Spec2("IndexedDB 2")}} 
+ +

Browser compatibility

+ +
+ + +

{{Compat("api.IDBOpenDBRequest")}}

+
+ +

See also

+ + -- cgit v1.2.3-54-g00ecf