Linux编程之：五个常见PHP数据库问题

Load_files.sql:
INSERT INTO files VALUES ( 1, 1, 'test1.jpg', 'files/test1.jpg' );
INSERT INTO files VALUES ( 2, 1, 'test2.jpg', 'files/test2.jpg' );

Users.sql:
DROP TABLE IF EXISTS users;
CREATE TABLE users (
id MEDIUMINT,
login TEXT,
password TEXT
);

Load_users.sql:
INSERT INTO users VALUES ( 1, 'jack', 'pass' );
INSERT INTO users VALUES ( 2, 'jon', 'pass' );

function get_user( $name )
{
$dsn = 'mysql://root:password@localhost/bad_multi1';
$db =& DB::Connect( $dsn, array() );
if (PEAR::isError($db)) { die($db->getMessage()); }

$res = $db->query( "SELECT id FROM users WHERE login=?",
array( $name ) );
$uid = null;
while( $res->fetchInto( $row ) ) { $uid = $row[0]; }

return $uid;
}

function get_files( $name )
{
$uid = get_user( $name );

$rows = array();

$dsn = 'mysql://root:password@localhost/bad_multi2';
$db =& DB::Connect( $dsn, array() );
if (PEAR::isError($db)) { die($db->getMessage()); }

$res = $db->query( "SELECT * FROM files WHERE user_id=?",
array( $uid ) );
while( $res->fetchInto( $row ) ) { $rows[] = $row; }

return $rows;
}

$files = get_files( 'jack' );

var_dump( $files );
?>

function get_files( $name )
{
$rows = array();

$dsn = 'mysql://root:password@localhost/good_multi';
$db =& DB::Connect( $dsn, array() );
if (PEAR::isError($db)) { die($db->getMessage()); }

$res = $db->query(
"SELECT files.* FROM users, files WHERE
users.login=? AND users.id=files.user_id",
array( $name ) );
while( $res->fetchInto( $row ) ) { $rows[] = $row; }

return $rows;
}

$files = get_files( 'jack' );

var_dump( $files );
?>