解锁 IndexedDB

Question

解锁 IndexedDB

3

尝试使用IndexedDB。我编写了一个创建新表和索引并返回回调的函数。

但是当我尝试使用该函数时，它停止工作 - 在“onsuccess”状态之后，我得到了“onblocked”状态，并且“onupgradeneeded”没有运行...

如何避免阻塞数据库？

crtTable(db_name, table, indexes, callback) {
    console.log("Initiate table creation");
    let isSupport:boolean = this.checkDbSupport();
    if(!isSupport) return;

    let version;
    let openRequest = indexedDB.open(db_name);
    openRequest.onsuccess = (event) => {
        console.log("Opening DB and find version");
        version = (event.target as any).result.version;

        //I GOT DB VERSION AND NOW I TRYING TO CLOSE IT!
        (event.target as any).result.close();

        version++;

        console.log("reopen DB with new version")
        let openRequest = indexedDB.open(db_name, version);

        openRequest.onblocked = (event) => {
            console.log("blocked");
        }

        openRequest.onupgradeneeded = (event) => {
            console.log("update running")
            let db = (event.target as any).result;

            let transaction = db.createObjectStore(table[0], { keyPath: table[1] });
            for(let index of indexes) {
                transaction.createIndex(index[0], index[0], { unique: index[1] });
            }
            transaction.oncomplete = (event) => {
                console.log("indexes setted");
            }
            callback("updated");
            console.log("updated");
        };

        openRequest.onsuccess = (event) => {
            openRequest.result.close();
            callback("success");
            console.log("success");
        };

        openRequest.onerror = (event) => {
            openRequest.result.close();
            callback("error");
            console.log("error");
        };
    };
}

- s.spirit

1个回答

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- Nadir Laskar · Accepted Answer

在升级数据库到新版本之前，您需要关闭其他数据库连接。

IDBOpenDBRequest.onblocked事件处理程序是blocked事件的事件处理程序。当出现版本更改但数据库仍然在某个地方（即未关闭）使用时（即使已发送versionchange事件），应触发此事件来触发upgradeneeded。

https://developer.mozilla.org/en-US/docs/Web/API/IDBOpenDBRequest/onblocked

更新:

你试图在onsuccess和onerror事件上关闭它，但由于数据库已经打开并调用了onblocked事件，因此这些事件不会被调用。请尝试在onblocked事件上关闭数据库。

openRequest.onblocked = (event) => {
      (event.target as any).result.close();
      console.log("blocked");
 }