how to check if user exist in oracle db using c# forms?

xxghostxx tak

hi all

I just create two c# forums one for users to register and the second one for users to login into third forums to for example I want to know how to do this ?

I tried to do it by creating this method ,but its not working

public bool isUserExist(string un, string password)

{

bool status = false;

try

{

string connstring = "data source=test_db;user id=system;password=password;";

string statementcmd = "SELECT uname FROM register_user Where uname=@un";

using (OracleConnection conn = new OracleConnection(connstring))

{

using (OracleCommand cmd = new OracleCommand())

{

cmd.Connection = conn;

cmd.Parameters.Add("@un", un);

cmd.CommandText = statementcmd;

if (conn.State != ConnectionState.Open)

{

conn.Open();

OracleDataReader reader = cmd.ExecuteReader();

if (!reader.Read())

MessageBox.Show("User Name Not Found");

if (!password.Equals(reader["password"].ToString()))

{

status = true;

MessageBox.Show("Incorrect Password");

}

catch (Exception ex)

{

MessageBox.Show(ex.ToString());

status = false;

}

return status;

}

3 Replies

Know the answer? Post it — somebody with the same question will find it here.

xxghostxx tak12y ago
thank u both guys but first of all im using oracle syntax and I think u confused between mysql and oracle syntax
second I had changed the method from private to public coz I was not able to see the textbox1 at query bellow

"select count(*)from employee where ename='" + txtUserName.Text + "'";
after all here is the whole code after converting it from mysql to racle syntax and i had change it alite bit
the code wont work when I run it
Error message is
unhandled exception ...
error message number is ORA-00911 Invalid character
hope 2get some help around here ^_^
public void isUserExist(string un, string password)
{
string connectionstring = GetConnectionString();
using (OracleConnection conn = new OracleConnection())
{
conn.ConnectionString = connectionstring;
conn.Open();

OracleCommand cmd = new OracleCommand();
string str = "select count(*)from register_user where uname='" +textBox1.Text + "';";
cmd = new OracleCommand(str, conn);
int count = Convert.ToInt32(cmd.ExecuteScalar());
if (count > 0)
MessageBox.Show("User Name Exist");
else
MessageBox.Show("user name not exist");
}
}
}
}

thanks alot :D
0
Abhay Shanker12y ago
Try As below:-

static private string GetConnectionString()
{
// To avoid storing the connection string in your code,
// you can retrieve it from a configuration file.
return "Data Source=myserver.server.com;Persist Security Info=True;" +
"User ID=myUserID;Password=myPassword;Unicode=True";
}

// This will open the connection and query the database
static private void ConnectAndQuery()
{
string connectionString = GetConnectionString();
using (OracleConnection connection = new OracleConnection())
{
connection.ConnectionString = connectionString;
connection.Open();
str = "select count(*)from employee where ename='" + txtUserName.Text + "'";
com = new SqlCommand(str, connection);
int count = Convert.ToInt32(com.ExecuteScalar());
if (count > 0)
{
lblMessage.Text = "username exist";
}
else
{
lblMessage.Text = "username doesnot exist";
}
}
0
Satyapriya Nayak12y ago
protected void btn_check_Click(object sender, EventArgs e)
        {
            SqlConnection con = new SqlConnection(connStr);
            con.Open();
            str = "select count(*)from employee where ename='" + txtUserName.Text + "'";
            com = new SqlCommand(str, con);
            int count = Convert.ToInt32(com.ExecuteScalar());
            if (count > 0)
            {
                lblMessage.Text = "username exist";
            }
            else
            {
                lblMessage.Text = "username doesnot exist";
            }
        }
0