ADO.NET之判斷重複記錄

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();

        }

        //連接配接資料庫的字元串

        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 = "";//定義字元串變量

            System.Data.OleDb.OleDbConnection tem_conn =

                new System.Data.OleDb.OleDbConnection(connstr);//連接配接資料庫

            System.Data.OleDb.OleDbCommand tem_comm;//定義OleDbCommand類

            tem_conn.Open();//打開資料庫的連接配接

            //設定SQL語句，查找要添加的記錄

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

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

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

            int RecordCount = 0;//定義變量

            if (tem_comm.ExecuteScalar() == null)//如果查詢為空

                RecordCount = 0;

            else

                RecordCount = (int)tem_comm.ExecuteScalar();//傳回查找結果的個數

            tem_conn.Close();//關閉連接配接

            tem_comm.Dispose();//釋放資源

            tem_conn.Dispose();//釋放資源

            return RecordCount;//傳回查詢記錄數量

        }

        private void button1_Click(object sender, EventArgs e)

        {

            if (isHomologyNote("tb_BasicTable", "Number", "Name", textBox1.Text, textBox2.Text) > 0)//如果查詢結果大于0

                MessageBox.Show("已有重複記錄");//彈出提示框

            else//可以對該記錄進行添加

                MessageBox.Show("無記錄，可以添加");

        }

    }

}