c# ado 连接数据库　六步曲

2018-06-18 05:06:45来源：未知阅读 ()

建立连接分为六步：
1.定义连接字符串，oracle 的连接字符串为：

private static string connString = "Data Source=192.168.1.130:1521/mydata;Persist Security Info=True;User ID=em_test;Password=test123;Unicode=True";

2.根据连接字符串成连接
3.打开连接
4.实例命令对象
5.操作
6.关闭连接

看一个例子：

using System; using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
using System.Data.OracleClient;

namespace OpenCloseDB
{
    public partial class Form1 : Form
    {
        public Form1()
        {             InitializeComponent();
        }

        private void button1_Click(object sender, EventArgs e)
        {
            OracleConnection connection = null;
            int num = 0;
            string message = "";
            String sql = "select count(*) from ex_user";
            try
            {
                string connString = "Data Source=mydata;Persist Security Info=True;User ID=test;Password=huikk123;Unicode=True";

                // 创建connection对象
                connection = new OracleConnection(connString);

                // 打开连接
                connection.Open();
                OracleCommand command = new OracleCommand(sql, connection);
                num = int.Parse(command.ExecuteScalar().ToString());
                message = string.Format("共有{0}条用户信息!", num);
                MessageBox.Show(message);
            }
            catch (Exception ex)
            {

                MessageBox.Show("出现异常"+ex.Message);
            }
            finally
            {
                if (connection != null)
                {
                    connection.Close();
                }
            }
        }
    }
}