js+html5操作sqlite数据库的方法

本文实例讲述了js+html5操作sqlite数据库的方法。分享给大家供大家参考，具体如下：

//copyright by lanxyou lanxyou[at]gmail.com
var lanxDB=function(dbname){
  var db=openDatabase(dbname,'1.0.0','',65536);
  return{
    //返回数据库名
    getDBName:function(){
      return dbname;
    },
    //初始化数据库，如果需要则创建表
    init:function(tableName,colums){
      this.switchTable(tableName);
      colums.length>0?this.createTable(colums):'';
      return this;
    },
    //创建表，colums:[name:字段名,type:字段类型]
    createTable:function(colums){
      var sql="CREATE TABLE IF NOT EXISTS " + this._table ;
      var t;
      if (colums instanceof Array && colums.length>0){
 t=[];
 for (var i in colums){
   t.push(colums[i].name+' '+colums[i].type);
 }
 t=t.join(', ');
      }else if(typeof colums=="object"){
 t+=colums.name+' '+colums.type;
      }
      sql=sql+" ("+t+")";
      var that=this;
      db.transaction(function (t) { 
 t.executeSql(sql) ;
   })
    },
    //切换表
    switchTable:function(tableName){
      this._table=tableName;
      return this;
    },
    //插入数据并执行回调函数，支持批量插入
    //data为Array类型，每一组值均为Object类型，每一个Obejct的属性应为表的字段名，对应要保存的值
    insertdata:function(data,callback){
      var that=this;
      var sql="INSERT INTO "+this._table;
      if (data instanceof Array && data.length>0){
 var cols=[],qs=[];
 for (var i in data[0]){
   cols.push(i);
   qs.push('?');
 }
 sql+=" ("+cols.join(',')+") Values ("+qs.join(',')+")";
      }else{
 return false;
      }
      var p=[],
 d=data,
 pLenth=0,
 r=[];
      for (var i=0,dLength=d.length;i0){
   db.transaction(function (t) { 
     t.executeSql(sql,p.shift(),queue,that.onfail);
   })
 }else{
   if (callback){
     callback.call(this,r);
   }
 }
      }
      queue();
    },
    _where:'',
    //where语句，支持自写和以对象属性值对的形式
    where:function(where){
      if (typeof where==='object'){
 var j=this.toArray(where);
 this._where=j.join(' and ');
      }else if (typeof where==='string'){
 this._where=where;
      }
      return this;
    },
    //更新数据，data为属性值对形式
    updatedata:function(data,callback){
      var that=this;
      var sql="Update "+this._table;
      data=this.toArray(data).join(',');
      sql+=" Set "+data+" where "+this._where;
      this.doQuery(sql,callback);
    },
    //根据条件保存数据，如果存在则更新，不存在则插入数据
    savedata:function(data,callback){
      var sql="Select * from "+this._table+" where "+this._where;
      var that=this;
      this.doQuery(sql,function(r){
 if (r.length>0){
   that.updateData(data,callback);
 }else{
   that.insertData([data],callback);
 }
      });
    },
    //获取数据
    getdata:function(callback){
      var that=this;
      var sql="Select * from "+that._table;
      that._where.length>0?sql+=" where "+that._where:"";
      that.doQuery(sql,callback);
    },
    //查询，内部方法
    doQuery:function(sql,callback){
      var that=this;
      var a=[];
      var bb=function(b,result){
 if (result.rows.length){
   for (var i=0;i0?sql+=" where "+that._where:'';
      that.doQuery(sql,callback);
    },
    //删除表
    dropTable:function(){
      var sql="DROP TABLE IF EXISTS "+this._table;
      this.doQuery(sql);
    },
    _error:'',
    onfail:function(t,e){
      this._error=e.message;
      console.log('----sqlite:'+e.message);
    },
    toArray:function(obj){
      var t=[];
      obj=obj || {};
      if (obj){
 for (var i in obj){
   t.push(i+"='"+obj[i]+"'");
 }
      }
      return t;
    }
  }
}

希望本文所述对大家Javascript程序设计有所帮助。