A Practical Approach to Object-Relational Mapping in PHP Page 9

<?php
class DataField 
{
    function TYPE_STRING() 
    { 
        return 1; 
    }
    function TYPE_NUMERIC() 
    { 
        return 2; 
    }
    var $db_type = null;
    var $is_primary_key = null;
    var $value = null;
    function DataField($col_type, $is_pk) 
    {
        $this->db_type = $col_type;
        $this->is_primary_key = $is_pk;
    }
}
?>

Lines 2 and 3 essentially define two constants, though they are really static methods and are called as such
(see lines 7 and 8 in the Hippo code above, and line 7 in ArmedHippo). Declaring them this way subjects
them to the same scope and inheritance rules as other methods.

BusinessBase::addField() (called by Hippo and ArmedHippo) adds a field to
$records:

<?php
function addField( $db_col_name, $field ) 
{    
    $this->record[$db_col_name] = $field;
}
?>

BusinessBase::load() looks like this:

<?php
function load($id) 
{
    $this->find_id_field();
    $conn = mysql_connect('localhost', 'hippo_user', 'hippo_user');
    mysql_select_db('hippos');
    $query = 'select * from '.$this->table_name.' where '.$this->_id_field." = $id";
    $fetched_record = mysql_fetch_assoc( mysql_query($query) );
    foreach ($this->record as $col_name=>$field)
    $this->record[$col_name]->value = $fetched_record[$col_name];
    application_utility_tasks();
}
?>

BusinessBase::load() calls find_id_field()
in line 3 to locate the primary key field, and store its name in $this->_id_field for later use.
The method then opens the database (line 4), builds a SELECT query (line 7), and executes it
(line 9). Lines 11-13 move the data into $record, where it can be retrieved with a statement
like this from Hippo:

$this->id = $this->getDBValue(‘id’);