Index: trunk/kernel/units/general/cat_dbitem.php
===================================================================
diff -u -r3709 -r3757
--- trunk/kernel/units/general/cat_dbitem.php	(.../cat_dbitem.php)	(revision 3709)
+++ trunk/kernel/units/general/cat_dbitem.php	(.../cat_dbitem.php)	(revision 3757)
@@ -59,7 +59,7 @@
 	
 	function Update($id=null, $system_update=false)
 	{
-		$this->VirtualFields['ResourceId'] = true;
+		$this->VirtualFields['ResourceId'] = Array();
 		$this->SetDBField('Modified', adodb_mktime() );
 		$this->SetDBField('ModifiedById', $this->Application->GetVar('u_id'));
 		
@@ -68,7 +68,10 @@
 		$this->generateFilename();
 		}
 		
-		return parent::Update($id, $system_update);
+		$ret = parent::Update($id, $system_update);
+		
+		unset($this->VirtualFields['ResourceId']);
+		return $ret;
 	}
 	
 	function checkFilename()
@@ -319,16 +322,47 @@
 	 */
 	function assignToCategory($category_id, $is_primary = false)
 	{
-		$check_sql = '	SELECT CategoryId
-						FROM '.TABLE_PREFIX.'CategoryItems
-						WHERE (ItemResourceId = '.$this->GetDBField('ResourceId').') AND (PrimaryCat = 1)';
-		$primary_category_id = $this->Conn->GetOne($check_sql);
-		if (!$primary_category_id) $is_primary = true;
+		$table = TABLE_PREFIX.'CategoryItems';
+		$key_clause = '(ItemResourceId = '.$this->GetDBField('ResourceId').')';
 		
-		if ($primary_category_id == $category_id) return ;
+		// get all cateories, where item is in
+		$sql = 'SELECT PrimaryCat, CategoryId FROM '.$table.' WHERE '.$key_clause;
+		$item_categories = $this->Conn->GetCol($sql, 'CategoryId');
+		if (!$item_categories) {
+			$item_categories = Array();
+			$primary_found = false;
+		}
 		
-		$sql = 'INSERT INTO '.TABLE_PREFIX.'CategoryItems (CategoryId,ItemResourceId,PrimaryCat) VALUES (%s,%s,%s)';
-		$this->Conn->Query( sprintf($sql, $category_id, $this->GetDBField('ResourceId'), $is_primary ? 1 : 0) );
+		// find primary category 
+		foreach ($item_categories as $item_category_id => $primary_found) {
+			if ($primary_found) {
+				break;
+			}
+		}
+		
+		if ($primary_found && ($item_category_id == $category_id) && !$is_primary) {
+			// want to make primary category as non-primary :(
+			return true;
+		}
+		else if (!$primary_found) {
+			$is_primary = true;
+		}
+		
+		if ($is_primary && $item_categories) {
+			// reset primary mark from all other categories
+			$sql = 'UPDATE '.$table.' SET PrimaryCat = 0 WHERE '.$key_clause;
+			$this->Conn->Query($sql);
+		}
+		
+		// UPDATE & INSERT instead of REPLACE because CategoryItems table has no primary key defined in database
+		if (isset($item_categories[$category_id])) {
+			$sql = 'UPDATE '.$table.' SET PrimaryCat = '.($is_primary ? 1 : 0).' WHERE '.$key_clause.' AND (CategoryId = '.$category_id.')';
+			$this->Conn->Query($sql);
+		}
+		else {
+			$sql = 'INSERT INTO '.$table.' (CategoryId,ItemResourceId,PrimaryCat) VALUES (%s,%s,%s)';
+			$this->Conn->Query( sprintf($sql, $category_id, $this->GetDBField('ResourceId'), $is_primary ? 1 : 0) );
+		}
 	}
 	
 	/**