WebSQL为客户端关系型数据库，但浏览器支持不是很好，目前chrome支持的最好，其他浏览器部分版本支持。所以这里只做为学习了解，如果有数据库（mysql）经验的同学，能比较好的理解这一块内容。话不多说，直接上代码：
<body>
<button id="btn-create">创建user数据表</button>
<button id="btn-insert">插入数据</button>
<button id="btn-query">查询数据</button>
<button id="btn-update">修改数据</button>
<button id="btn-delete">删除数据</button>
<button id="btn-drop">删除user数据表</button>
</body>
//模拟一条user数据
let user = {
username: "creatto",
password: "123123",
info: "beaconApp开发团队中一员"
};
/**
* 创建数据库 或者此数据库已经存在 那么就是打开数据库
* name: 数据库名称
* version: 版本号
* displayName: 对数据库的描述
* estimatedSize: 设置数据的大小
* creationCallback: 回调函数(可省略)
*/
let db = openDatabase("MySql", "1.0", "我的数据库描述", 1024 * 1024);
let result = db ? "数据库创建成功" : "数据库创建失败";
console.log(result);
const USER_TABLE_SQL = "create table if not exists userTable (id integer primary key autoincrement,username varchar(12)," +
"password varchar(16),info text)";
const INSERT_USER_SQL = "insert into userTable (username, password,info) values(?,?,?)";
const QUERY_USER_SQL = "select * from userTable";
const UPDATE_USER_SQL = "update userTable set password = ? where username = ?";
const DELETE_USER_SQL = "delete from userTable where username = ?";
const DROP_USER_SQL = "drop table userTable";
const findId = id => document.getElementById(id);
//创建数据表
function createTable() {
db.transaction(tx => {
tx.executeSql(USER_TABLE_SQL, [],(tx, result) => {
alert('创建user表成功:' + result);
}, (tx, error) => {
alert('创建user表失败:' + error.message);
})
})
}
//插入数据
function insertData(user) {
db.transaction(tx => {
tx.executeSql(INSERT_USER_SQL,[user.username, user.password, user.info],(tx, result) => {
alert('添加数据成功:');
}, (tx, error) => {
alert('添加数据失败:' + error.message);
})
})
}
//查询数据
function queryData() {
db.transaction(tx => {
tx.executeSql(QUERY_USER_SQL, [],(tx, result) => {
console.log(result);
},(tx, error) => {
console.log('查询失败: ' + error.message)
})
})
}
//修改数据
function updateData(user) {
db.transaction(tx => {
tx.executeSql(UPDATE_USER_SQL, [user.password, user.username],(tx, result) => {
alert("修改数据成功")
}, (tx, error) => {
alert("修改数据失败:" + error.message)
})
})
}
//删除数据
function deleteData(user) {
db.transaction(tx => {
tx.executeSql(DELETE_USER_SQL, [user.username],(transaction, resultSet) => {
alert("删除数据成功")
}, (transaction, error) => {
alert("删除数据失败:" + error.message)
})
})
}
//删除数据表
function dropTable() {
db.transaction(tx => {
tx.executeSql(DROP_USER_SQL, [],(transaction, resultSet) => {
alert("删除数据表成功")
}, (transaction, error) => {
alert("删除数据表失败:" + error.message)
})
})
}
/**
* 点击事件 增删查改
*/
let btnCreate = findId("btn-create");
let btnInsert = findId("btn-insert");
let btnQuery = findId("btn-query");
let btnUpdate = findId("btn-update");
let btnDelete = findId("btn-delete");
let btnDrop = findId("btn-drop");
btnCreate.onclick = () => createTable();
btnInsert.onclick = () => insertData(user);
btnQuery.onclick = () => queryData();
btnUpdate.onclick = () => {
user.password = "111666666"; //修改密码
updateData(user);
};
btnDelete.onclick = () => deleteData(user);
btnDrop.onclick = () => dropTable();
