diff --git a/chapter-02/1.mapping.md b/chapter-02/1.mapping.md
index 0107869..5903112 100644
--- a/chapter-02/1.mapping.md
+++ b/chapter-02/1.mapping.md
@@ -9,7 +9,7 @@ Use `xorm.IMapper` interface to set the name mapping rule. There are three rules
 SnakeMapper is the default. You can change it use `SetMapper`.
 
 ```Go
-engine.SetMapper(SameMapper{})
+engine.SetMapper(core.SameMapper{})
 ```
 
 And you should notice:
@@ -18,8 +18,8 @@ And you should notice:
 * Tables's mapping rule could be different from Columns':
 
 ```Go
-engine.SetTableMapper(SameMapper{})
-engine.SetColumnMapper(SnakeMapper{})
+engine.SetTableMapper(core.SameMapper{})
+engine.SetColumnMapper(core.SnakeMapper{})
 ```
 
 When a struct auto mapping to a database's table, the below table describes how they change to each other: