update语句操作二进制有有关问题，该怎么写

update语句操作二进制有问题，该如何写
表a(id,图片一，图片二)
下面语句update有问题 该如何写？
<%response.buffer=true
formsize=Request.TotalBytes
formdata=request.binaryread(formsize)
bncrlf=chrB(13)&chrB(10)
divider=leftB(formdata,clng(instrb(formdata,bncrlf))-1)
datastart=instrb(formdata,bncrlf&bncrlf)+4
dataend=instrb(datastart+1,formdata,divider)-datastart
mydata=midb(formdata,datastart,dataend)
set rec=server.createobject("ADODB.recordset")
sql="update a set 图片二='"&mydata&"'mydata where id="& Request.QueryString("id")
rec.Open sql,session("connection_string"),3,3
rec.close
set rec=nothing

[解决办法]
Access: 将字段的类型设为“OLE对象”

VBScript code

set rec=server.createobject("ADODB.recordset")sql="SELECT * FROM TableName"rec.Open sql,session("connection_string"),3,3rec.AddNewrec("id") = Request.QueryString("id")rec("图片二").appendchunk mydatarec.closeset rec=nothing