Web Front-endH5 TutorialXiaoqiang's road to HTML5 mobile development (20) - HTML5 Web SQL Database
1. Introduction to Web Database
The WebSQL database API is actually not a component of the HTML5 specification, but a separate specification. It manipulates the client's database through a set of APIs. Safari, Chrome, Firefox, Opera and other mainstream browsers already support WebSQL Database
WebSQL database has three core methods:
1) Open the database openDatabase() method:
This method creates a database object, either using an existing database or creating a new database.
2) Transaction transaction() method:
This method can be used to control transaction processing, perform commit operations or rollback operations.
3) Execute SQL command executeSql() method:
This method is used to execute SQL queries.
2. Use Web database operation
<!DOCTYPE HTML>
<html>
<head>
<meta charset="urf-8"/>
</head>
<body>
<script type="text/javascript">
//创建数据库
var db = window.openDatabase("dawanganban", "1.0","数据库描述",20000);
//创建数据表
db.transaction(function(tx) {
tx.executeSql("CREATE TABLE test (id int UNIQUE, mytitle TEXT, timestamp REAL)");
});
//插入数据
db.transaction(function(tx) {
tx.executeSql("INSERT INTO test (id, mytitle, timestamp) values(?, ?, ?)", [1, "WEB Database", new Date().getTime()], null, null);
});
//插入数据
db.transaction(function(tx) {
tx.executeSql("INSERT INTO test (id, mytitle, timestamp) values(?, ?, ?)", [2, "DaWanGanBan", new Date().getTime()], null, null);
});
//删除数据
/*
db.transaction(function(tx){
tx.executeSql("DELETE FROM test where mytitle=?",["WEB Database"],null,null);
});
*/
//db.transaction(function(tx) {
// tx.executeSql("DROP TABLE qqs");
//})
//db.transaction(function(tx) {
// tx.executeSql("update test set mytitle=? where mytitle = 'fsafdsaf'",['xp'],null,null);
//});
//查询数据
db.transaction(function(tx) {
tx.executeSql("SELECT * FROM test", [],
function(tx, result) {
for(var i = 0; i < result.rows.length; i++){
document.write('<b>' + result.rows.item(i)['mytitle'] + '</b><br />');
}
}, function(){
alert("error");
});
});
</script>
</body>
</html>
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