3月9日连接数据库（简单的增删改查）

1、增加：

//增加    private void button2_Click(object sender, EventArgs e)    {         string uname=textBox2.Text;        string upass=textBox1.Text;

       SqlConnection conn = new SqlConnection("server=.;database=data1220;user=sa;pwd=sa");        conn.Open();

       SqlCommand cmd = conn.CreateCommand();        cmd.CommandText = "insert into table1 values('"+uname+"', '"+upass+"')";

       int count=cmd.ExecuteNonQuery();        if (count > 0)        {            MessageBox.Show("增加成功");        }        else        {            MessageBox.Show("增加失败");        }        conn.Close();    }

 

执行结果：

      

 

2、删除

//删除        private void button4_Click(object sender, EventArgs e)        {            string code = textBox3.Text;

           SqlConnection conn = new SqlConnection("server=.;database=data1220;user=sa;pwd=sa");            conn.Open();

           SqlCommand cmd = conn.CreateCommand();            cmd.CommandText = "delete from table1 where code="+code;            cmd.ExecuteNonQuery();            conn.Close();        }

 

3、修改

//修改    private void button3_Click(object sender, EventArgs e)    {        string uname = textBox2.Text;        string upass = textBox1.Text;        string code = textBox3.Text;

       SqlConnection conn = new SqlConnection("server=.;database=data1220;user=sa;pwd=sa");        conn.Open();

       SqlCommand cmd = conn.CreateCommand();        cmd.CommandText = "update table1 set uname='"+uname+"',upass='"+upass+"'where code="+code;        int count=cmd.ExecuteNonQuery();        if (count > 0)        {            MessageBox.Show("修改成功");        }        else        {            MessageBox.Show("修改失败");        }        conn.Close();    }

 

4、查询

//查询        private void button1_Click(object sender, EventArgs e)        {            string uname=textBox2.Text;            string upass=textBox1.Text;            //连接数据库            SqlConnection conn = new SqlConnection("server=.;database=data1220;user=sa;pwd=sa");            conn.Open();            //写执行语句            SqlCommand cmd = conn.CreateCommand();  //通过conn创建SqlCommand对象            cmd.CommandText = "select *from table1 where uname='"+uname+"' and upass='"+upass+"' ";            SqlDataReader dr = cmd.ExecuteReader();  //执行查询，返回SqlDataReader对象

           if (dr.Read())            {                MessageBox.Show("登陆成功");            }            else            {                MessageBox.Show("登陆失败");            }            conn.Close();        }

转载于:https://www.cnblogs.com/tzq9308/p/4330287.html