求ID字段生成算法,该怎么处理

求ID字段生成算法
现需由系统产生一种唯一标识记录的ID字段,希望各位高手提供下...位数不限,但不能出现重复的概率...

------解决方案--------------------
自定义啊 
use test
go
if exists(select * from sysobjects where name='P_Order' and type='P' )
drop proc P_order
go
create proc P_Order
@MaxId int,
@Date varchar(10),
@NewId varchar(20)
as
begin
select @MaxId=Id from TB_Order
select @Date=CONVERT(VARCHAR(10),GETDATE(),112) 
set @NewId=@Date+ right(cast(power(10,4) as varchar)+@MaxId,4)
insert into dbo.test([Name],EName,[NewId]) values('lee','lfs',@NewId)
end

exec P_Order
------解决方案--------------------
HTML code

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML>
<HEAD>
<TITLE> New Document </TITLE>
<META NAME="Generator" CONTENT="EditPlus">
<META NAME="Author" CONTENT="">
<META NAME="Keywords" CONTENT="">
<META NAME="Description" CONTENT="">
<script type="text/javascript">
function UUID(){
    this.id = this.createUUID();
}

UUID.prototype.valueOf = function(){ return this.id; }
UUID.prototype.toString = function(){ return this.id; }

UUID.prototype.createUUID = function(){
  
    var dg = new Date(1582, 10, 15, 0, 0, 0, 0);
    var dc = new Date();
    var t = dc.getTime() - dg.getTime();
    var tl = UUID.getIntegerBits(t,0,31);
    var tm = UUID.getIntegerBits(t,32,47);
    var thv = UUID.getIntegerBits(t,48,59) + '1'; // version 1, security version is 2
    var csar = UUID.getIntegerBits(UUID.rand(4095),0,7);
    var csl = UUID.getIntegerBits(UUID.rand(4095),0,7);

    var n = UUID.getIntegerBits(UUID.rand(8191),0,7) + 
            UUID.getIntegerBits(UUID.rand(8191),8,15) + 
            UUID.getIntegerBits(UUID.rand(8191),0,7) + 
            UUID.getIntegerBits(UUID.rand(8191),8,15) + 
            UUID.getIntegerBits(UUID.rand(8191),0,15); // this last number is two octets long
    return tl + tm  + thv  + csar + csl + n; 
}

UUID.getIntegerBits = function(val,start,end){
    var base16 = UUID.returnBase(val,16);
    var quadArray = new Array();
    var quadString = '';
    var i = 0;
    for(i=0;i<base16.length;i++){
        quadArray.push(base16.substring(i,i+1));    
    }
    for(i=Math.floor(start/4);i<=Math.floor(end/4);i++){
        if(!quadArray[i] || quadArray[i] == '') quadString += '0';
        else quadString += quadArray[i];
    }
    return quadString;
}

UUID.returnBase = function(number, base){
    return (number).toString(base).toUpperCase();
}

UUID.rand = function(max){
    return Math.floor(Math.random() * (max + 1));
}

function newUID(){
    document.getElementById("txtUID").value = new UUID();
}
</script>
</HEAD>

<BODY>
<input type="text" id="txtUID" style="width:300px" value=""/>
<br/>
<input type="button" id="btnUID" value="Create UID" onclick="newUID();"/>

</BODY>
</HTML>