#4 OO and database design with PHPMVC

[Anonymous]

Just trying to work out how I should reference the database
if I am using objects. Currently the database needs to be
instantiated in the scope of the action server.

But if I'm calling a class and want to build an object I want
the object to populate all the data itself.

So how do I reference the database within the object I've
created when it performs various actions on the object ie
save, load etc.

All the examples I've seen using PHPMVC and ADODB
define the database within the scope of the action which
means I have to make the database a global variable and
then reference it within the object - not a pretty thing.

I'd like to simply call the methods on an object and let the
methods access a database reference.

Thanks
Andrew

[John Wildenauer]

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Andrew,

Do you mean something like this:

Q: How to access a DataSource reference in my business classes

A:
Within our Action class \(or ActionForm\) we can retrieve a
reference to the data source instance. Then we can create a
new instance of our business class, passing the data source
reference to the business object as a constructor parameter,
or using a setter method.

When out business class processing is complete, we can
safely disconnect from the database. If we did not retrieve
the data source
as a reference \("=&"\) but just used a copy \("="\) and then
disconnected from the database, we could not reconnect again
during this request as the original datasource instance will
think it is still connected to the database.

class MyAction extends Action \{
...
function execute\($mapping, $form, &$request, &$response\) \{

//////////
// Call our business logic from here

// Retrieve a reference \("=&"\) to the datasource
$db =& $this->actionServer->getDataSource\($dsKey\);

// Using the constructor
$myApp = new MyBusinessClass\($db\);

// Or using the setter method
$myApp->setDataSource\($db\);

// Do some business logic processing
$myApp->processSomething\(\);

//////////
// Cleanup
// We can disconnect here if we access $db as a
reference \("=&"\)
$db->disconnect\(\);

\}
\}

MyBusinessClass \{

// The datasource reference
var $dataSource = NULL; 

// Set the data source reference using a constructor
function BusinessClass\($db\) \{
$this->dataSource = $ds;
\}

// Or set the data source reference using a setter method
function setDataSource\($db\) \{
$this->dataSource = $ds;
\}

function processSomething\(...\) \{
$ds = $this->dataSource;
...
\}
\}

References relating to php.MVC/Database usage with Pear::DB
or ADOdb

Pear::DB database access in php.MVC
http://phpmvc.net/docs/guides/guidesIdx.php?doc=pear-db

ADOdb Database Access in php.MVC
http://phpmvc.net/docs/guides/guidesIdx.php?doc=adodb-db

John