日期:2014-05-16  浏览次数:20775 次

HTML5 Web 数据库的使用

针对HTML5 Web数据库的封装如下:

? 备注来自网络:

//自定义的数据库操作类   
var Cls_websql = function(db_name,config){   
       
        //初始化变量   
        var cf= config?config:{},   
        cfg = {   
            version: cf.version?cf.version:'1.0',desc: cf.desc?cf.desc:'数据库'+db_name,size: cf.size?cf.size:10*1024   
        },   
    
        log= function(msg, cat, src){   
            if (window['console'] !== undefined && console.log) {   
                console[cat && console[cat] ? cat : 'log'](msg);   
            }   
        },   
    
           
       //还不成熟,sql中不能包含"?",例"select user where title like 'tb?'"   
        formatSql= function(sql,data){   
            var count=0;   
            return sql.replace(/(\?)/g, function(a,b){   
                return data[count++];   
            });   
        },   
    
           
       //初始化数据库   
        db= function(){   
            if(window['openDatabase'] !== undefined){   
                log("数据库连接成功");   
                return openDatabase(db_name, cfg.version , cfg.desc , cfg.size);   
            }else{   
                log("数据库连接失败");   
                return null;   
            }   
        }();   
    
     this.db= db;   
       
   //执行sql操作   
    this.execSql= function(sql,data,success,failure){   
        if(!db){   
            log("请先初始化数据库和表。");   
            return;   
        }   
        if(!data){   
            data= [];   
        }   
        if (success === undefined){   
            success = function(tx, results){   
                log("操作成功:"+formatSql(sql,data));   
            }   
        }   
        var errfun= toString.call(failure) === '[object Function]'?   
                    function(tx, err){   
                        failure.call(this,tx,err,formatSql(sql,data));   
                    } :   
                    function(tx, err){   
                        log("操作失败! msg:"+err.message+" sql:"+formatSql(sql,data));   
                    };   
        //真正执行sql的地方
        db.transaction(function(tx){   
            try{   
                tx.executeSql(sql,data,success,errfun)   
            }catch(e){   
                log("数据库执行失败:"+e.message);   
            }   
        });   
    };   
    
};   

?

使用如下:

<!DOCTYPE html>
<html>
<head>
<title>测试 WebSQL Database</title>
<meta charset="utf-8" />
</head>
<body onload="init()">
<h1>Web SQL Database</h1>
<div id="info"></div>
<div id="result"></div>
<button onclick="javascript:query();" value="查询"></button>
</body>
<script src="../js/WebSQLDatabase.js"></script>
<script>
    function init() {
        var websql = new Cls_websql("stationList", {});
        websql.execSql('CREATE TABLE IF NOT EXISTS SETS (key unique, value)');
    }
    function query() {
        var websql = new Cls_websql("stationList", {});
        websql.execSql("select * from sets ", [], function() {
            alert('success');
        }, function() {
            alert('failure');
        })
    }
</script>
</html>

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