Implemented the balance field of Leases as part of a single query. This not only reduces the number of queries required, it also allows balance to be a sortable column, so that we can determine which customers are overdue.

git-svn-id: file:///svn-source/pmgr/branches/invoice_receipt_20090629/site@251 97e9348a-65ac-dc4b-aefc-98561f571b83

models/ledger_entry.php

@@ -32,6 +32,23 @@ class LedgerEntry extends AppModel {
 			'className' => 'Ledger',
 			'foreignKey' => 'credit_ledger_id',
 		),
+
+		'Ledger' => array(
+			'foreignKey' => false,
+			// conditions will be used when JOINing tables
+			// (such as find with LinkableBehavior)
+			'conditions' => array('OR' =>
+			    array('%{MODEL_ALIAS}.debit_ledger_id  = Ledger.id',
+				  '%{MODEL_ALIAS}.credit_ledger_id = Ledger.id')),
+
+			// finderQuery will be used when tables are put
+			// together across several querys, not with JOIN.
+			// (such as find with ContainableBehavior)
+			'finderQuery' => 'NOT-IMPLEMENTED',
+
+			'counterQuery' => ''
+		),
+
 	);
 
 	var $hasAndBelongsToMany = array(