oci_parse error message - php

Question

I get this error message, what does it mean and how to fix it?
Warning: oci_parse() expects parameter 1 to be resource, null given in /user_auth_fns.php on line 3
$conn = db_connect();
$result = oci_parse($conn, "select * from user where username='$username' and passwd = sha1('$password')");
if (!$result){
$err = oci_error();
echo "Could not log you in.";
exit;
}
$r = oci_execute($result);
if (!$r) {
$error = oci_error($conn);
echo "Could not log you in." . $error['message'];
exit;
}
function db_connect()
{
$db = "dbms";
if ($c=oci_connect("username", "password", $db)){
echo "Successfully connected to Oracle.\n";
OCILogoff($c);
} else {
$err = OCIError();
echo "Oracle Connect Error " . $err[text];
}
}
Edit 2 fixed the problem, another error message, what other compression function(other than SHA1) should use for oracle?
Warning: oci_execute() [function.oci-execute]: ORA-00904: "SHA1": invalid identifier in /user_auth_fns.php on line 10

Answer 1

I don't know what db_connect() is returning. Maybe it is just creating a connection by its own. Try this:
$conn = oci_connect("userName","password","hostName");
fill up the useName & password & hostName here. if you are having problem with hostName then try to put the whole connection string there. example:
$conn = oci_connect('userName', 'password', '(DESCRIPTION = (ADDRESS = (PROTOCOL = TCP)(HOST = )(PORT = )) (CONNECT_DATA = (SERVICE_NAME = ) (SID = )))');
then you can create a query like
$query="....";
then you can parse like this:
$result = oci_parse($conn, $query);
if you succeed in querying then $result holds Boolean value 'true'.

Answer 2

Your $conn variable is null. How do you instantiate that?
Edit
You instantiate $conn from db_connect(), which is not part of the standard PHP library so I can not tell you what's wrong with it other than it's returning null.
Edit 2
You're db_connect() doesn't return anything. Additionally, you close the connection immediately after opening it. Try this:
function db_connect()
{
$db = "dbms";
if ($c=oci_connect("username", "password", $db)){
echo "Successfully connected to Oracle.\n";
//OCILogoff($c); // You probably don't want to close the connection here
return $c;
} else {
$err = OCIError();
echo "Oracle Connect Error " . $err[text];
}
}

Answer 3

It means that $conn has no value, it is null. What did you want to have in $conn? Go back and check that.