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;i<dLength;i++){

var k=[];

for (var j in d[i]){

k.push(d[i][j]);

}

p.push(k);

}

var queue=function(b,result){

if (result){

r.push(result.insertId ||result.rowsAffected);

}

if (p.length>0){

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;i<result.rows.length;i++){

a.push(result.rows.item(i));

}

}else{

a.push(result.rowsAffected);

}

if (callback){

callback.call(that,a);

}

}

db.transaction(function (t) {

t.executeSql(sql,[],bb,that.onfail) ;

})

},

//根据条件删除数据

deleteData:function(callback){

var that=this;

var sql="delete from "+that._table;

that._where.length>0?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;

}

}

}

/*

examples:

var db=new lanxDB('testDB');

db.init('channel_list',[{name:'id',type:'integer primary key autoincrement'},{name:'name',type:'text'},{name:'link',type:'text'},{name:'cover',type:'text'},{name:'updatetime',type:'integer'},{name:'orders',type:'integer'}]);

db.init('feed_list',[{name:'parentid',type:'integer'},{name:'feed',type:'text'}]);

db.switchTable('channel_list').insertData([{name:'aa',link:'ss',updatetime:new Date().getTime()},{name:'bb',link:'kk',updatetime:new Date().getTime()}]);

db.where({name:'aa'}).getData(function(result){

console.log(result);//result为Array

});

db.where({name:'aa'}).deleteData(function(result){

console.log(result[0]);//删除条数

});

db.where({name:'bb'}).saveData({link:'jj'},function(result){

console.log(result);//影响条数

})

})

*/

希望本文所述对大家JavaScript程序设计有所帮助。