webSQL 常常使用的几个必要函数

webSQL 经常使用的几个必要函数

仅供参考：

var html5rocks = {};

html5rocks.webdb = {};

html5rocks.webdb.db = null; //将sqldb存到一个全局变量中

openDB();



//创建database

function openDB(){

    var dbSize = 5 * 1024 * 1024; // 5MB

    html5rocks.webdb.db = openDatabase("JoyOfficialApp", "1.0", "JoyOfficialApp DB", dbSize);

    createTable();

}



//创建表

function createTable(){

    var db = html5rocks.webdb.db;

    db.transaction(function(tx) {

        tx.executeSql("CREATE TABLE IF NOT EXISTS MYFOLLOWINFO(ID INTEGER PRIMARY KEY ASC,INFOID TEXT,TYPETAG TEXT)", []);

        tx.executeSql("CREATE TABLE IF NOT EXISTS UPLOADFOLLOW(ID INTEGER PRIMARY KEY ASC,INFOID TEXT,TYPETAG TEXT)", []);

    },dbOnError,dbOnSuccess);

}



//执行sql发生异常时

function dbOnError(tx, e){

    console.log("There has been an error: " + e.message);

}



//sql调用成功后的函数

function dbOnSuccess(tx, r) {

    //alert("create table success");

    //console.log("success");

}



//删除数据库中表内容的函数

function deleteTable(table){

     var db = html5rocks.webdb.db;

     db.transaction(function(tx){

        tx.executeSql("DELETE FROM "+table, [],dbOnSuccess,dbOnError);

     });

 }







//判断数据库中是否已经插入数据

 var db = html5rocks.webdb.db;

    db.transaction(function(tx) {

        tx.executeSql("SELECT * FROM aaa WHERE INFOID=? ", [id], function(tx, rs) {

                 //枚举记录

                 if (rs.rows.length > 0) {

                                         for ( i = 0; i < rs.rows.length; i++) {

                                                             var item = rs.rows.item(i);

                                                             var bbb=item.INFOID；

                                                             var ccc=item.TYPETAG；

                       

                    }

             }

             //执行插入数据的操作

             if (rs.rows.length == 0) {

                           tx.executeSql("INSERT INTO aaa(INFOID,TYPETAG) VALUES (?,?)", [id, type], function() {



                            }, dbOnError);

                }



               



         },,dbOnError);

 });