mySQL n00b

Heya.... I've just recently started piddling around with PHP, and found I liked it (wehey :D)
I've started on a side project of a simple login/register page, which connects to my mySQL db, checks the info, then lets users in or whatever... however, I have NO idea how to get PHP to talk to the db.... any starters?




Thanks for yer help in advance :)

Well, since you're new to PHP, I'm guessing you don't know a whole lot about the language.. so, here's a pretty basic snippet that will show you what you can/want to do.. it might help you out a bit..

PHP Code:

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<?
  //set your mysql connect variables
    $mysql['host'] = "localhost";    //host address
    $mysql['user'] = "user";         //username
    $mysql['pass'] = "pass";         //password
    $mysql['maindb'] = "db_name";    //database name
    $mysql['table'] = "table_name";  //table name
  //make an empty mysql query and mysql data array
    $mysql['query'] = array();
    $mysql['data'] = array();
  //connect to mysql host with user:pass combination
    //note: @ will stop errors from being displayed
    @mysql_connect($mysql['host'], $mysql['user'], $mysql['pass']) or die("MySQL Error: Database connection error");
  //select the mysql database
    @mysql_select_db($mysql['maindb']) or die("MySQL Error: Database selection error");

  
  //make a mysql query to select information from the database
    $mysql['query'][0] = "SELECT field1, field2 FROM $mysql[table] WHERE field1='some_data'";
  //make a mysql query to insert information into the database
    $mysql['query'][1] = "INSERT INTO $mysql[table] VALUES('$some_data', '$some_data2', '$some_other_data')";
  //make a mysql query to update information in the database
    $mysql['query'][2] = "UPDATE $mysql[table] SET field1='some_other_data' WHERE field1='some_data'";

  //query the database for each mysql query which does not return data (INSERT, UPDATE)
    mysql_query($mysql['query'][1]);
    mysql_query($mysql['query'][2]);
  //query the database for the mysql query that does return data (SELECT)
    $query = mysql_query($mysql['query'][0]);
  //fetch the data that the query returned
    //use just a flat out mysql_fetch_array($query) to get one result
      $mysql['data'][0] = mysql_fetch_array($query);
      //print out the array
        echo "<xmp>";
        print_r($mysql['data'][0]);
        echo "</xmp>";
    //OR, use a while loop to fetch all data that fits the SELECT
      //store what the current record is
      $i = 0;
      while($mysql['data'][1] = mysql_fetch_array($query)){
        //print out the current returned results
          echo "<xmp>";
          print_r($mysql['data'][1]);
          echo "</xmp>";
        $i++; //increase the current record number
      }
?>

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I realize that just giving you that with my crude comments will probably not do a lot, but, you did ask for how to interact with a database, and that's how.. Anyway, I suggest looking up some MySQL tutorials, www.3dbuzz.com has some good PHP/MySQL VTMs.

PS: With your login system, you're going to want to use MySQL SELECTs to check the information.. another code snippet.. this is pretty much all you would have to do, with a lot of customization, of course:

PHP Code:

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<?
  //mysql connection stuff goes here
    $mysql['table'] = "users";
  if(!isset($_POST['user'], $_POST['pass'])){
    //form hasn't been submitted, show it
?>
<form method="post">
  username: <input type="text" name="user">
  password: <input type="password" name="pass">
  <input type="submit" value="login">
</form>
<?
  }else{
    //form has been submitted, check login information

      //note: for ease of use, ONLY select the password
      //      if the password can't be located from the WHERE fields, the password is wrong
      //note2: if you want to return an error if the account even exists, you can add to this
      //note3: 'LIMIT 1' limits the number of records returned to 1

      //set up the query to match the login information to a database record
        $query = "SELECT pass FROM $mysql[table] WHERE user='$_POST[user]' AND pass='$_POST[pass]' LIMIT 1";
      //query the database
        $query = mysql_query($query);
      //fetch the query array
        $query = mysql_fetch_array($query);
      //note: if you are looping through the query, you must use different variable names
      //      for the mysql_query() and the mysql_fetch_array()
      if(!empty($query[0])){
        //query was not empty, login information is correct
        echo "you logged in successfully!";
      }else{
        //query was empty, login information was incorrect
        echo "there was an error with your login information!";
      }
  }
?>

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