Xiaoqiang's road to HTML5 mobile development (20) - HTML5 Web SQL Database-H5 Tutorial-php.cn

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Xiaoqiang's road to HTML5 mobile development (20) - HTML5 Web SQL Database

黄舟

Jan 22, 2017 pm 01:59 PM

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

##1) Open the database openDatabase() method:

This method creates a database object. You can use an existing database or create a new database.

Xiaoqiangs road to HTML5 mobile development (20) - HTML5 Web SQL Database

2) Transaction transaction() method:

This method can be used to control transaction processing, perform commit operations or rollback operations.

Xiaoqiangs road to HTML5 mobile development (20) - HTML5 Web SQL Database

3) Execute SQL command executeSql() method:

This method is used to execute SQL queries.

Xiaoqiangs road to HTML5 mobile development (20) - HTML5 Web SQL Database

3. Example

<!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 = &#39;fsafdsaf&#39;",[&#39;xp&#39;],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(&#39;<b>&#39; + result.rows.item(i)[&#39;mytitle&#39;] + &#39;</b><br />&#39;);   
                    }   
                }, function(){  
                    alert("error");  
                });   
            });   
        </script>  
    </body>  
</html>

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Xiaoqiangs road to HTML5 mobile development (20) - HTML5 Web SQL Database

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