SQL操作

*VB                                               需求： 工程------》引用                    Microsoft ActiveX Data Objects  *  Library        Microsoft ActiveX Data Objects Recordset  *  Library   

      连接

Dim cn As New ADODB.Connection
Set cn = New ADODB.Connection
cn.ConnectionString = "Driver={sql server};server=(local);uid=sa;pwd=sa;database=数据库名"
cn.ConnectionTimeout = 30
cn.Open

      读取/查询

Dim rs As New ADODB.Recordset
Set rs = New ADODB.Recordset
rs.Open "select * from xxx", cn
Dim str As String
str = rs.Fields("floorName").Value

      写入/更改

Dim sql As String

sql = "update xxx " 

cn..Execute sql

     关闭

rs.close

cn.close

*C# -- Web                                            需求：    using System.Data;     using System.Data.SqlClient;

      连接

     string conStr = "Data Source=(local);Initial Catalog=数据库名;User ID=sa;Password=sa";

      SqlConnection conn = new SqlConnection(conStr);
            conn.Open();

       读取/查询

      string sql = "select * from 表"
            // 创建命令（SqlCommand）对象(cmd)
       SqlCommand cmd = new SqlCommand();
       cmd.Connection = conn; // 指示命令发给哪个数据库
       cmd.CommandType = CommandType.Text; // 指示是什么类型的命令
       cmd.CommandText = sql;
       SqlDataReader read = cmd.ExecuteReader();         //SqlDataReader 只能打开一个 

       if(read.Read())

            string readStr = read.GetSqlString(0).ToString();

        写入/更改

      sql = "update 表 “;

      if(cmd.ExecuteNonQuery() != 0)

               //读取成功

       关闭

        read.Close();
        conn.Close();

*VC                                                              需求：#include <afxdb.h>       

     ::CoInitialize(NULL);  
    CDatabase con;
    CString conStr = "Data Source=(local);";     //或     conStr = "DSN=已经存在的dns;UID=sa;PWD=sa";
    try
    {

    连接

     con.OpenEx(conStr);//连接数据库                           ConnectionTimeout = 5;    连接超时时间    CommandTimeout = 10;  查询等命令超时时间

   读取/查询

       CRecordset read(&con);
        CString sql = "select * from 表";
        read.Open(CRecordset::forwardOnly, sql, CRecordset::readOnly);
        while(!read.IsEOF())
        {
            CString str;
            read.GetFieldValue((int)0, str);
            read.MoveNext();
        }  
        read.Close();

       写入/更改
        sql = "update 表 " ;  //更新数据
        con.ExecuteSQL(sql);

       关闭
        con.Close();
    }
    catch (...)
    {
        //Error
        con.Close();
    }   
    ::CoUninitialize();