HOWTO: CONVERT A PROPEL OBJECT TO AND FROM ARRAYS (HASHES)

1. Propel contains methods to convert to and from array, but they aren't generated by default. To get toArray() and fromArray(), add the following to build.properties:

    propel.addGenericAccessors = true # gets you toArray()
    propel.addGenericMutators = true  # gets you fromArray()
   

2. Regenerate your classes.

3. Now you can:

    $obj->toArray(BasePeer::TYPE_FIELDNAME) // see BasePeer for other
                                            // key styles
   

   (fromArray() presumably works analogously, but I haven't tried it.)

HOWTO: SELECT DATABASE AT RUNTIME

(For example, if you want to connect to different databases from dev, stage and live sites and don't want to, or can't modify runtime-conf.xml.)

Instead of initialising Propel via:

Propel::init('/path/to/myproject-conf.php');

do something like:

// $config comes from the '/path/to/myproject-conf.php'
// (as built by propel-gen)

$config = array(
  'propel' => array(
    'datasources' => array(
      'skirepublic' => array(
        'adapter' => 'mysql',
        'connection' => array(
          'phptype' => 'mysql',
          'database' => Config::get("database"),
          'hostspec' => Config::get("hostname"),
          'username' => Config::get("username"),
          'password' => Config::get("password")
        ),
      ),
      'default' => 'skirepublic',
    ),
  ),
);

Propel::setConfiguration($config);
Propel::initialize();

GOTCHA: EMPTY OBJECTS AREN'T SAVED TO THE DATABASE

Completely empty objects don't get saved:

$p = new Person();
$p->save(); // this doesn't save anything to the database

You need to make some change to the Person first:

$p = new Person();
$p->setFirstName("Clem");
$p->save(); // this will commit to the database

GOTCHA: DELETE() DOES AN IMPLICIT SAVE()

The delete() method does an implicit save(); it doesn't (for example) set a flag that's acted upon by a save().

GOTCHA: DELETES PROPAGATE ACROSS OBJECTS

Deletes propagate in the database, but not in their representative objects. So, for example, if you have:

$album = new Album();
$track = new Track();
$track->setName("XXX");

$album->addTrack($track);
$album->save(); // album and associated track written to database

assertFalse($album->isDeleted());
assertFalse($track->isDeleted());

$album->delete();

assertTrue($album->isDeleted());
assertTrue($track->isDeleted()); // this will FAIL!    

GOTCHA: COUNT*() RETURNS THE DATABASE COUNT, NOT THE OBJECT COUNT

The count[Column]() method returns the number of relevant items in the database, not the number of relevant items in the object. (i.e. count*() doesn't flush all changed objects to disk before doing the count.) So, for example:

$album = new Album();
$album->save();

assertEqual($album->countTracks(), 0);

$album->addTrack(new Track());
$album->addTrack(new Track());
$album->addTrack(new Track());

assertEqual($album->countTracks(), 0); // still 0!
$album->save();
assertEqual($album->countTracks(), 3); // now it's 3

HOWTO: GET A DATABASE HANDLE

i.e. the equivalent of mysql_connect().

If you're using MySQL, it's probably:

Propel::getConnection()->getResource()

The mysql_query() will use the current connection by default, though, so if a connection has already been established by Propel and you're happy to be lazy, you can do mysql_query(...) without specifying a database connection and it will do the right thing.

HOWTO: GENERATE A schema.xml FROM AN EXISTING DATABASE

Haven't tried it, but see

http://propel.phpdb.org/trac/wiki/Users/Documentation/1.2/HowTos/ExistingDatabases