学步园

 C# 数据库操作固定模板

 string path = Application.StartupPath + "//db1.mdb";
        OleDbConnection con = new OleDbConnection(@"Provider=Microsoft.Jet.OLEDB.4.0;Data         Source=" + path + ";Persist Security Info=False");//创建连接对象,；连接字符串

        con.Open(); //连接数据库

增 :
 string sql = "insert  into t1(name,pwd)  values (@a,@b)";
             
  OleDbParameter p1 = new OleDbParameter("@a", textBox1.Text);
        OleDbParameter p2 = new OleDbParameter("@b", textBox2.Text);
        OleDbCommand com = new OleDbCommand(sql, ole);
               
        com.Parameters.Add(p1);
        com.Parameters.Add(p2);
        com.ExecuteNonQuery();

删:

 string sql = " delete from  t1 where name = @a";

 OleDbParameter p1 = new OleDbParameter("@a", textBox1.Text);
        OleDbCommand com = new OleDbCommand(sql, ole);
               
        com.Parameters.Add(p1);
        com.ExecuteNonQuery();

改:

 string sql = " update   t1 set  pwd = @a where  name = @b";

 OleDbParameter p1 = new OleDbParameter("@a", textBox1.Text);
        OleDbParameter p2 = new OleDbParameter("@b", textBox2.Text);
        OleDbCommand com = new OleDbCommand(sql, ole);
               
        com.Parameters.Add(p1);
        com.Parameters.Add(p2);
        com.ExecuteNonQuery();

查:

 string sql = "select  * from t2 where Name=@a and Pwd=@b";

        OleDbParameter p1 = new OleDbParameter("@a", textBox1.Text);
        OleDbParameter p2 = new OleDbParameter("@b", textBox2.Text);
        OleDbCommand com = new OleDbCommand(sql, con);
           
 com.Parameters.Add(p1);
        com.Parameters.Add(p2);

        OleDbDataReader dr = com.ExecuteReader();// 与前三者不同
        if (dr.Read())
        {
           MessageBox.Show("登录通过！");
        }