C# SQL 增 删 改 查

一、查

SqlConnection conn = new SqlConnection();

conn.ConnectionString = sqlb.ConnectionString;

conn.Open();

string sqlstr="";

SqlDataAdapter adap = new SqlDataAdapter(sqlstr, conn);

DataSet ds = new DataSet();

adap.Fill(ds);

DataTable dt = ds.Tables[0];

if(dt.Rows.Count==1)

{

MainForm2 mf = new MainForm2();

mf.Show();

this.Hide();

}

二、 删除

string sqlstr = "delete from d_user where realname='" + username + "'";

SqlCommand scd = new SqlCommand(sqlstr, conn);

int n = scd.ExecuteNonQuery();

if (n > 0)

{

MessageBox.Show("删除成功!");

}

三、插入增加

string sqlstr = "insert into d_user (username,dep,realname,cpnum,password,major) values (" + "'" + t_logname + "'," + "'" + t_dep + "'," + "'" + t_name + "','"+t_cpnum+"','"+"123','"+t_major+"')";

SqlCommand sqlcmd = new SqlCommand(sqlstr, conn);

n = sqlcmd.ExecuteNonQuery();

if (n > 0)

{

MessageBox.Show("保存成功");

}

else

{

MessageBox.Show("保存失败");

}

四、修改

string SQLstr = "update cslist set bzdm='" + bzdmstr + "',cs_content='" + bznrstr + "',bzfl='"+bzflstr+"',locationx='"+rowstr+"',locationy='"+colstr+"' where bzdm='"+bzdm+"'";

// MessageBox.Show(SQLstr);

SqlCommand sqlcmd = new SqlCommand(SQLstr, conn);

int n;

n = sqlcmd.ExecuteNonQuery();

if (n > 0)

{

MessageBox.Show("修改成功");

}