防注入代码应该如何使用？

<%
set conn=server.CreateObject("ADODB.Connection")
conn.connectionstring="driver=Microsoft Access Driver (*.mdb);DBQ="&Server.mappath("wd888.asp")
conn.open
%>
<%
dim sql_injdata,SQL_inj,SQL_Get
SQL_injdata="'| |and|exec|insert|select|delete|update|count|*|%|chr|mid|master|truncate|char|declare"
SQL_inj = split(SQL_Injdata,"|")

If Request.QueryString<>"" Then
For Each SQL_Get In Request.QueryString
For SQL_Data=0 To Ubound(SQL_inj)
if instr(LCase(Request.QueryString(SQL_Get)),Sql_Inj(Sql_DATA))>0 Then
Response.Write "<Script Language=JavaScript>alert('请不要在参数中包含非法字符尝试注入！ ');history.back(-1)</Script>"
Response.end
end if
next
Next
End If

If Request.Form<>"" Then
For Each Sql_Post In Request.Form
For SQL_Data=0 To Ubound(SQL_i