//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
})
})
*/
//javascript/241