javascript 用Javascript从数据库中检索值
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时间：2020-10-26 12:12:52 来源:igfitidea点击:
Retrieving value from database in Javascript
提问by prakash_d22
I am new to mobile application development with PhoneGap. I have created a form to add and show name, address and phone number of a student in SQLite database. But the problem is I don't know to retrieve and display the values in the text boxes.
我是使用 PhoneGap 进行移动应用程序开发的新手。我创建了一个表单，用于在 SQLite 数据库中添加和显示学生的姓名、地址和电话号码。但问题是我不知道在文本框中检索和显示值。
<!DOCTYPE HTML>
<html>
<head>
<title>Contact Example</title>
<script type="text/javascript" charset="utf-8" src="phonegap-1.4.1.js"></script>
<script type="text/javascript" charset="utf-8">
document.addEventListener("deviceready", onDeviceReady, false);
function onDeviceReady() {
var db = window.openDatabase("Database", "1.0", "PhoneGap Demo", 200000);
db.transaction(populateDB, errorCB, successCB);
}
function populateDB(tx) {
tx.executeSql('CREATE TABLE IF NOT EXISTS DEMO (sname ,saddress ,sphone)');
}
function errorCB(tx, err) {
alert("Error processing SQL: "+err);
}
// Transaction success callback
//
function successCB() {
alert("success!");
}
function add(tx){
var name=document.getElementById('n');
var address=document.getElementById('a');
var phone=document.getElementById('p');
tx.executeSql('INSERT INTO DEMO (sname ,saddress ,sphone) VALUES ('"+name+"','"+address+"','"+phone+"')');
//tx.executeSql('INSERT INTO DEMO (id, data) VALUES (2, "Second row")');
}
function show(tx){
var name=document.getElementById('n');
tx.executeSql('SELECT * FROM DEMO WHERE (sname='"+name+"')');
document.f.n.value=name;
document.f.a.value=//??;
document.f.p.value=//??;
}
</script>
</head>
<body>
<form name="f" method="get" action="">
Name :<input type="text" id="n" size="10"></input><br>
Add :<input type="text" id="a" size="10"></input><br>
Phone :<input type="text" id="p" size="10"></input><br>
<input type="button" value="Add" onClick="add()">
<input type="button" value="Show" onClick="show()">
</form>
</body>
</html>
回答by Tamkeen
document.addEventListener("deviceready", onDeviceReady, false);
function onDeviceReady()
{
alert("onDeviceReady called");
}
function populateDB(tx)
{
tx.executeSql('CREATE TABLE IF NOT EXISTS DEMO (sname ,saddress ,sphone)');
var name=document.getElementById('n');
var address=document.getElementById('a');
var phone=document.getElementById('p');
tx.executeSql('INSERT INTO DEMO (sname ,saddress ,sphone) VALUES ('"+name.value+"','"+address.value+"','"+phone.value+"')');
}
function errorCB(tx, err)
{
alert("Error processing SQL: "+err);
}
// Transaction success callback
//
function successCB()
{
alert("success!");
}
function add()
{
var db = window.openDatabase("Database", "1.0", "PhoneGap Demo", 200000);
db.transaction(populateDB, errorCB, successCB);
}
for more see link here
有关更多信息，请参阅此处的链接
//show data from db
// Transaction success callback
function show()
{
var db = window.openDatabase("Database", "1.0", "PhoneGap Demo", 200000);
db.transaction(queryDB, errorCB);
}
// Query the database
function queryDB(tx)
{
tx.executeSql('SELECT * FROM DEMO', [], querySuccess, errorCB);
}
// Query the success callback
function querySuccess(tx, results)
{
var len = results.rows.length;
console.log("DEMO table: " + len + " rows found.");
for (var i=0; i<len; i++){
console.log("Row = " + i + " sname = " + results.rows.item(i).sname + " saddress = " + results.rows.item(i).saddress);
}
}
// Transaction error callback
function errorCB(err)
{
console.log("Error processing SQL: "+err.code);
}
回答by Abilash Raghu
Inside your code for save call db.transaction(populateDB, errorCB, successCB)
在保存调用 db.transaction(populateDB, errorCB, successCB) 的代码中
The function will return to
该函数将返回
function populateDB(tx) {
var rr=escape(JSON.stringify(onedata));//here onedata is data you want to save I use json data here.
tx.executeSql('CREATE TABLE IF NOT EXISTS LeadInfo (data)');
tx.executeSql('INSERT INTO LeadInfo (data) VALUES ("'+ rr +'")');
alert("Insert")
}
function errorCB(tx, err) {
//alert("Error processing SQL Insert: "+err);
}
function successCB() {
// alert("success!");
}
For retrieval you can use following:
对于检索，您可以使用以下内容：
function queryDB(tx) {
tx.executeSql('SELECT * FROM LeadInfo', [], querySuccess, errorCB);
}
function querySuccess(tx, results) {
var tablereport="";
if (results != null && results.rows != null) {
for (var i = 0; i < results.rows.length; i++) {
var row =unescape(results.rows.item(i).data);
var obj = JSON.parse(row);
tablereport+='<a href="#"><span style="font-size:18px; font-weight:400; padding:10px 0px 10px 0px;">'+JSON.stringify(obj.lead_name)+'</span><span style="padding: 10px 16px;width: 100px;float: right;margin-top: -33px;margin-right: -80px;font-size:14px"></span><br>';
tablereport+='</li>';
tablereport+='</li>';
}
}
}
function errorCB(err) {
alert("Error processing SQL Retrive: "+err.code);
}
