* baseDAO: fix error can't set cache for the updated table.

lib/base/dao/dao.class.php

@@ -991,6 +991,8 @@ class baseDAO
             /* Real-time save log. */
             if(dao::$realTimeLog && dao::$realTimeFile) file_put_contents(dao::$realTimeFile, $sql . "\n", FILE_APPEND);
 
+            $table = $this->table;
+
             $this->reset();
 
             /* Force to query from master db, if db has been changed. */
@@ -998,11 +1000,11 @@ class baseDAO
 
             $result = $this->dbh->exec($sql);
 
-            if($this->table)
+            if($table)
             {
                 /* 更新表的缓存时间。*/
                 /* Update the table cache time. */
-                $table = str_replace(array('`', '"'), '', $this->table);
+                $table = str_replace(array('`', '"'), '', $table);
                 $this->setCache($table);
             }