ADO.NET之判断重复记录

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;

namespace IsDistinct

{

    public partial class Frm_Main : Form

    {

        public Frm_Main()

        {

            InitializeComponent();

        }

        //连接数据库的字符串

        string connstr = @"Provider=SQLOLEDB;Data Source=.\SQLEXPRESS;AttachDbFilename=C:\DataBase\db_TomeTwo.mdf;

Integrated Security = SSPI;Persist Security Info=False";

        public int isHomologyNote(string Table, string term1, string term2, string Value1, string Value2)

        {

            string tem_sql = "";//定义字符串变量

            System.Data.OleDb.OleDbConnection tem_conn =

                new System.Data.OleDb.OleDbConnection(connstr);//连接数据库

            System.Data.OleDb.OleDbCommand tem_comm;//定义OleDbCommand类

            tem_conn.Open();//打开数据库的连接

            //设置SQL语句，查找要添加的记录

            tem_sql = "select top 1 * From " + Table + " where " + term1 + " = '" +

                Value1 + "' and " + term2 + " = '" + Value2 + "'";

            tem_comm = new System.Data.OleDb.OleDbCommand(tem_sql, tem_conn);//执行SQL语句

            int RecordCount = 0;//定义变量

            if (tem_comm.ExecuteScalar() == null)//如果查询为空

                RecordCount = 0;

            else

                RecordCount = (int)tem_comm.ExecuteScalar();//返回查找结果的个数

            tem_conn.Close();//关闭连接

            tem_comm.Dispose();//释放资源

            tem_conn.Dispose();//释放资源

            return RecordCount;//返回查询记录数量

        }

        private void button1_Click(object sender, EventArgs e)

        {

            if (isHomologyNote("tb_BasicTable", "Number", "Name", textBox1.Text, textBox2.Text) > 0)//如果查询结果大于0

                MessageBox.Show("已有重复记录");//弹出提示框

            else//可以对该记录进行添加

                MessageBox.Show("无记录，可以添加");

        }

    }

}