diff --git a/src/ORM/DataObject.php b/src/ORM/DataObject.php
index 7451422ce..d5e61b9d9 100644
--- a/src/ORM/DataObject.php
+++ b/src/ORM/DataObject.php
@@ -3039,29 +3039,33 @@ class DataObject extends ViewableData implements DataObjectInterface, i18nEntity
         $limit = null,
         $containerClass = DataList::class
     ) {
-
+        // Validate arguments
         if ($callerClass == null) {
             $callerClass = get_called_class();
-            if ($callerClass == self::class) {
-                throw new \InvalidArgumentException('Call <classname>::get() instead of DataObject::get()');
+            if ($callerClass === self::class) {
+                throw new InvalidArgumentException('Call <classname>::get() instead of DataObject::get()');
             }
-
-            if ($filter || $sort || $join || $limit || ($containerClass != DataList::class)) {
-                throw new \InvalidArgumentException('If calling <classname>::get() then you shouldn\'t pass any other'
+            if ($filter || $sort || $join || $limit || ($containerClass !== DataList::class)) {
+                throw new InvalidArgumentException('If calling <classname>::get() then you shouldn\'t pass any other'
                     . ' arguments');
             }
-
-            return DataList::create(get_called_class());
+        } elseif ($callerClass === self::class) {
+            throw new InvalidArgumentException('DataObject::get() cannot query non-subclass DataObject directly');
         }
-
         if ($join) {
-            throw new \InvalidArgumentException(
+            throw new InvalidArgumentException(
                 'The $join argument has been removed. Use leftJoin($table, $joinClause) instead.'
             );
         }
 
-        $result = DataList::create($callerClass)->where($filter)->sort($sort);
-
+        // Build and decorate with args
+        $result = DataList::create($callerClass);
+        if ($filter) {
+            $result = $result->where($filter);
+        }
+        if ($sort) {
+            $result = $result->sort($sort);
+        }
         if ($limit && strpos($limit, ',') !== false) {
             $limitArguments = explode(',', $limit);
             $result = $result->limit($limitArguments[1], $limitArguments[0]);
@@ -3173,35 +3177,32 @@ class DataObject extends ViewableData implements DataObjectInterface, i18nEntity
     }
 
     /**
-     * Return the given element, searching by ID
+     * Return the given element, searching by ID.
      *
-     * @param string|int $callerClassOrID The class of the object to be returned (optional if called from extending class)
-     * @param int|bool $id The id of the element or bool to represent cache if ID is passed as fist argument
-     * @param bool $cache See {@link get_one()}
+     * This can be called either via `DataObject::get_by_id(MyClass::class, $id)`
+     * or `MyClass::get_by_id($id)`
+     *
+     * @param string|int $classOrID The class of the object to be returned, or id if called on target class
+     * @param int|bool $idOrCache The id of the element, or cache if called on target class
+     * @param boolean $cache See {@link get_one()}
      *
      * @return static The element
      */
-    public static function get_by_id($callerClassOrID, $id = null, $cache = true)
+    public static function get_by_id($classOrID, $idOrCache = null, $cache = true)
     {
-        if (is_numeric($callerClassOrID)) {
-            // Alternate signature to allow calling as MyDataObject::get_by_id($id)
-            $cache = is_null($id) ? true : (bool)$id;
-            $id = $callerClassOrID;
-            $callerClass = get_called_class();
-            if (__CLASS__ === $callerClassOrID) {
-                user_error("DataObject::get_by_id called without providing object class", E_USER_WARNING);
-            }
-        } else {
-            $callerClass = $callerClassOrID;
-        }
+        // Shift arguments if passing id in first or second argument
+        list ($class, $id, $cached) = is_numeric($classOrID)
+            ? [get_called_class(), $classOrID, isset($idOrCache) ? $idOrCache : $cache]
+            : [$classOrID, $idOrCache, $cache];
 
-        if (!is_numeric($id)) {
-            user_error("DataObject::get_by_id passed a non-numeric ID #$id", E_USER_WARNING);
+        // Validate class
+        if ($class === self::class) {
+            throw new InvalidArgumentException('DataObject::get_by_id() cannot query non-subclass DataObject directly');
         }
 
         // Pass to get_one
-        $column = static::getSchema()->sqlColumnForField($callerClass, 'ID');
-        return DataObject::get_one($callerClass, array($column => $id), $cache);
+        $column = static::getSchema()->sqlColumnForField($class, 'ID');
+        return DataObject::get_one($class, [$column => $id], $cached);
     }
 
     /**