Applying patch from 'Thorsten Buss'.

Fixes issues in DboSource, where mismatching types on join columns could result in incorrect query generation.
Fixes #708

cake/libs/model/datasources/datasource.php

@@ -503,6 +503,7 @@ function insertQueryData($query, $data, $association, $assocData, &$model, &$lin
 
 		foreach ($keys as $key) {
 			$val = null;
+			$type = null;
 
 			if (strpos($query, $key) !== false) {
 				switch ($key) {
@@ -526,13 +527,16 @@ function insertQueryData($query, $data, $association, $assocData, &$model, &$lin
 								$val = '';
 							}
 						}
+						$type = $model->getColumnType($model->primaryKey);
 					break;
 					case '{$__cakeForeignKey__$}':
 						foreach ($model->__associations as $id => $name) {
 							foreach ($model->$name as $assocName => $assoc) {
 								if ($assocName === $association) {
 									if (isset($assoc['foreignKey'])) {
 										$foreignKey = $assoc['foreignKey'];
+										$assocModel = $model->$assocName;
+										$type = $assocModel->getColumnType($assocModel->primaryKey);
 
 										if (isset($data[$model->alias][$foreignKey])) {
 											$val = $data[$model->alias][$foreignKey];
@@ -561,7 +565,7 @@ function insertQueryData($query, $data, $association, $assocData, &$model, &$lin
 				if (empty($val) && $val !== '0') {
 					return false;
 				}
-				$query = str_replace($key, $this->value($val, $model->getColumnType($model->primaryKey)), $query);
+				$query = str_replace($key, $this->value($val, $type), $query);
 			}
 		}
 		return $query;