删除与某个子值相关联的整个记录 [英] delete entire record which is associated with a certain child value
本文介绍了删除与某个子值相关联的整个记录的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我想使用输入的子值删除数据库中的整个记录这是我尝试过的代码
i want to delete the entire record in the database using the child value entered this is the code i tried for it
<body>
User Name:
<input type="text" name="user_name" id="user_name" placeholder="enter text"/><br><br>
Enter Email:
<input type="text" name="user_name" id="user_name2" placeholder="enter email" />
<br><br>
<input type="button" value="Save" onclick="save_user();" />
<input type="button" value="delete" onclick="delete_user();" />
<script>
var tblUsers = document.getElementById('tbl_users_list');
var databaseRef = firebase.database().ref('users/');
var rowIndex = 1;
var uid;
var childKey;
var childData;
databaseRef.once('value', function(snapshot) {
snapshot.forEach(function(childSnapshot) {
childSnapshot.key;
childSnapshot.val();
var row = tblUsers.insertRow(rowIndex);
var cellId = row.insertCell(0);
var cellName = row.insertCell(1);
cellId.appendChild(document.createTextNode(childKey));
cellName.appendChild(document.createTextNode(childData.user_name));
cellName.appendChild(document.createTextNode(childData.user_name2));
rowIndex = rowIndex + 1;
});
});
function save_user(){
var user_name = document.getElementById('user_name').value;
var user_name2 = document.getElementById('user_name2').value;
uid = firebase.database().ref().child('users').push().key;
var data = {
user_id: uid,
user_name: user_name,
password: user_name2
}
var updates = {};
updates['/users/' + uid] = data;
firebase.database().ref().update(updates);
alert('The user is created successfully!');
reload_page();
document.writeln(uid);
}
function update_user(){
var user_name = document.getElementById('user_name').value;
var user_id = document.getElementById('user_id').value;
var data = {
user_id: user_id,
user_name: user_name
}
var updates = {};
updates['/users/' + user_id] = data;
firebase.database().ref().update(updates);
alert('The user is updated successfully!');
reload_page();
}
function delete_user(){
var user_id = document.getElementById('user_id').value;
firebase.database().ref().child('/users/' + user_id).remove();
alert('The user is deleted successfully!');
reload_page();
}
此处要引用和删除的子值将为user_name2
我想从此代码中删除与之关联的子值的记录
all i want from this code is to delete the record of the child value associated with it
我的数据库看起来像
例如，我要删除与孩子名字密码"ddd"相关的整个记录
推荐答案
Firebase仅在知道该节点的完整确切路径的情况下才能写入该节点.如果仅知道节点的属性值，则首先需要执行查询以查找具有该值的节点，然后编写这些节点.
Firebase can only write to a node if it knows the complete, exact path to that node. If you only know a property value of the node, you'll first need to execute a query to find the nodes with that value, and then write those nodes.
因此，在您的情况下，将是这样的:
So in your case that'd be something like:
let password = "ddd"; // hard-coded value, but this could also be read from the HTML
let ref = firebase.database().ref("users");
let query = ref.orderByChild("password").equalTo(password);
query.once("value").then(function(results) {
results.forEach(function(snapshot) {
snapshot.ref.remove();
})
})
这篇关于删除与某个子值相关联的整个记录的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
查看全文
