ACCESS实用技巧：ACCESS的参数化查询

//temp为Parameter对象可随便定义,OleDbType.VarChar指定为字符串,长度50
parm.Direction = ParameterDirection.Input;
//指定其类型输入参数
cmd.Parameters.Add(parm);
　cmd.Parameters["temp"].Value = "tsing";
//查询tsing,也可以写成cmd.Parameters[0]
　conn.Open();
　cmd.ExecuteReader();

Set parameter = command.CreateParameter (Name, Type, Direction, Size, Value)
参数同上
以下是实例，查询news表中所有tsing发表的新闻
------------------------------------------------------
et conn = Server.CreateObject("Adodb.Connection")
conn.ConnectionString = connString
conn.open()
set mycmd = Server.CreateObject("ADODB.Command")
mycmd.ActiveConnection=conn
mycmd.CommandText=sql
mycmd.Prepared = true
set mypar = mycmd.CreateParameter("temp",129,1,50,"tsing")
mycmd.Parameters.Append mypar
set myrs = mycmd.Execute

与上面基本相同不同的地方法是asp在对参数的表达上面不同
129为adChar，1就是指示输入参数(是其实是默认值)
大家请参阅MICROSOFT的ADOVB.Inc：

’---- ParameterDirectionEnum Values ----
Const adParamUnknown = 0
Const adParamInput = 1
Const adParamOutput = 2
Const adParamInputOutput = 3
Const adParamReturnValue = 4
’---- DataTypeEnum Values ----
Const adEmpty = 0
Const adTinyInt = 16
Const adSmallInt = 2
Const adInteger = 3
Const adBigInt = 20

Const adUnsignedTinyInt = 17
Const adUnsignedSmallInt = 18
Const adUnsignedInt = 19
Const adUnsignedBigInt = 21
Const adSingle = 4
Const adDouble = 5
Const adCurrency = 6
Const adDecimal = 14
Const adNumeric = 131
Const adBoolean = 11
Const adError = 10
Const adUserDefined = 132
Const adVariant = 12

Const adIDispatch = 9
Const adIUnknown = 13
Const adGUID = 72
Const adDate = 7
Const adDBDate = 133
Const adDBTime = 134
Const adDBTimeStamp = 135
Const adBSTR = 8
Const adChar = 129
Const adVarChar = 200
Const adLongVarChar = 201
Const adWChar = 130
Const adVarWChar = 202

Const adLongVarWChar = 203
Const adBinary = 128
Const adVarBinary = 204
Const adLongVarBinary = 205

using System;
using System.Data;
using System.Configuration;
using System.Web;
using System.Data.OleDb;
namespace acc_select
{
/// <summary>
/// accselect 的摘要说明
/// </summary>
public class accselect
{
//"Provider=Microsoft.Jet.OLEDB.4.0; Data Source=d:/dq/db1.mdb"
private string conn = ConfigurationManager.ConnectionStrings["tsingConnectionString"].ToString();
public string sql = string.Empty;
public int t = 4;
public object v = null;
public accselect()
{
}

/// <summary>
/// 构造函数，传递ACC参数查询语句
/// </summary>
/// <param name="strsql">strsql字符型</param>
public accselect(string strsql)
{
sql = strsql;
}
/// <summary>
/// 构造函数，传递ACC参数查询语句
/// </summary>
/// <param name="strsql">参数查询语句</param>
/// <param name="total">字节数</param>

public accselect(string strsql, int total)
{
sql = strsql;
t = total;
}
/// <summary>
/// 构造函数
/// </summary>
/// <param name="strsql">参数查询语句</param>
/// <param name="total">字节数</param>
/// <param name="value">OBJECT值</param>
public accselect(string strsql, int total, object value)
{

sql = strsql;
t = total;
v = value;
}
/// <summary>
/// getOdd方法返回OleDbDataReader
/// </summary>
/// <param name="odt">定义OleDbType类型</param>
/// <returns></returns>
public OleDbDataReader getOdd(OleDbType odt)
{
OleDbConnection conns = new OleDbConnection(this.conn);
OleDbCommand cmd = new OleDbCommand(this.sql, conns);

OleDbParameter parm = new OleDbParameter("temp", odt, this.t);
parm.Direction = ParameterDirection.Input;
cmd.Parameters.Add(parm);
cmd.Parameters[0].Value = this.v;
conns.Open();
OleDbDataReader oda = cmd.ExecuteReader();
cmd.Dispose();
return oda;
}
string Sql
{
get

{
return sql;
}
set
{
sql = value;
}
}
int T
{
get
{
return t;
}
set
{
t = value;
}
}
object V
{
get
{
return v;
}
set
{
v = value;

}
}
}
}
//调用方法
//accselect acc = new accselect();
//acc.sql = "select * from dtt where d_id=?";
//acc.t = 10;
//acc.v = 1;
//OleDbDataReader oda = acc.getOdd(OleDbType.VarChar);
//Repeater1.DataSource = oda;
//Repeater1.DataBind();

function acc_sql(sql,adotype,adodct,strlong,values)
dim connstring,mycmd,myrs,conn

connString="Provider=Microsoft.Jet.OLEDB.4.0; Data Source=" & Server.MapPath("db1.mdb")
set conn = Server.CreateObject("Adodb.Connection")
conn.ConnectionString = connString
conn.open()
set mycmd = Server.CreateObject("ADODB.Command")
mycmd.ActiveConnection=conn
mycmd.CommandText=sql
mycmd.Prepared = true
set mypar = mycmd.CreateParameter("temp",adotype,adodct,strlong,values)
mycmd.Parameters.Append mypar
set myrs = mycmd.Execute
set acc_sql=myrs
end function
’调用方法
’dim rs
’sql="select * from users where id=? order by id"
’set rs=acc_sql(sql,3,1,4,1)
’if not rs.eof then
’response.Write(rs(1))
’end if