Question

我想编写代码来从数据库中删除用户。这是代码（我使用的两种方法）：

[W 06:54:04.215 NotebookApp] The signatures database cannot be opened; maybe it is corrupted or encrypted. You may need to rerun your notebooks to ensure that they are trusted to run Javascript. The old signatures database has been renamed to /home/aulon/.local/share/jupyter/nbsignatures.db.bak and a new one has been created.
[E 06:54:04.218 NotebookApp] Unhandled error in API request
    Traceback (most recent call last):
      File "/home/aulon/.local/lib/python2.7/site-packages/notebook/base/handlers.py", line 516, in wrapper
        result = yield gen.maybe_future(method(self, *args, **kwargs))
      File "/home/aulon/.local/lib/python2.7/site-packages/tornado/gen.py", line 1055, in run
        value = future.result()
      File "/home/aulon/.local/lib/python2.7/site-packages/tornado/concurrent.py", line 238, in result
        raise_exc_info(self._exc_info)
      File "/home/aulon/.local/lib/python2.7/site-packages/tornado/gen.py", line 307, in wrapper
        yielded = next(result)
      File "/home/aulon/.local/lib/python2.7/site-packages/notebook/services/contents/handlers.py", line 124, in get
        path=path, type=type, format=format, content=content,
      File "/home/aulon/.local/lib/python2.7/site-packages/notebook/services/contents/filemanager.py", line 384, in get
        model = self._notebook_model(path, content=content)
      File "/home/aulon/.local/lib/python2.7/site-packages/notebook/services/contents/filemanager.py", line 344, in _notebook_model
        self.mark_trusted_cells(nb, path)
      File "/home/aulon/.local/lib/python2.7/site-packages/notebook/services/contents/manager.py", line 456, in mark_trusted_cells
        trusted = self.notary.check_signature(nb)
      File "/home/aulon/.local/lib/python2.7/site-packages/traitlets/traitlets.py", line 556, in __get__
        return self.get(obj, cls)
      File "/home/aulon/.local/lib/python2.7/site-packages/traitlets/traitlets.py", line 535, in get
        value = self._validate(obj, dynamic_default())
      File "/home/aulon/.local/lib/python2.7/site-packages/notebook/services/contents/manager.py", line 58, in _notary_default
        return sign.NotebookNotary(parent=self)
      File "/home/aulon/.local/lib/python2.7/site-packages/nbformat/sign.py", line 390, in __init__
        self.store = self.store_factory()
      File "/home/aulon/.local/lib/python2.7/site-packages/nbformat/sign.py", line 338, in factory
        return SQLiteSignatureStore(self.db_file)
      File "/home/aulon/.local/lib/python2.7/site-packages/nbformat/sign.py", line 147, in __init__
        self.db = self._connect_db(db_file)
      File "/home/aulon/.local/lib/python2.7/site-packages/nbformat/sign.py", line 171, in _connect_db
        os.rename(db_file, old_db_location)
    OSError: [Errno 2] No such file or directory
...

我面临的问题是：

“按钮”的“处理程序”中的第二个“console.log（email）”未显示正确的输出，而紧接在“goToDeleteUser（email）”之后的那个是。

2.当我使用'orderByChild'时，我需要将变量'email'传递给它中的'equalTo（）'，它在某种程度上是不接受的。

如何解决这些问题？请帮忙！

Answer 1

您有命名冲突：

handler: function(email) <--- Here 
{
    console.log(email);
    this.deleteUser(email);
}

处理程序传回了有关警报中输入的数据，但没有。警报所处的功能已经保留了email。只需删除email内的handler参数即可解决所有问题。

goToDeleteUser(email)
{ 
    console.log(email);
    let confirm = this.alertCtrl.create({
    title: 'Are you sure you want to delete this user ?',
        buttons: [
        { 
            text: 'Delete',
            handler: function()  <--- remove email has parameter
                {
                    console.log(email);
                    this.deleteUser(email);
                }
        }]
   });
   confirm.present();

}

deleteUser(email)
{  
    console.log(email);
    var userid;
    firebase.database().ref().child('users').orderByChild('email').equalTo(email).on("child_added",(snapshot)=>{
    userid=snapshot.val().uid}) ;
    console.log(userid);
    firebase.database().ref('users/userid').remove();
}

如何在firebase中的equalTo（）中使用变量？

1 个答案: