Mapper XML Files

The true power of MyBatis is in the Mapped Statements. This is where the magic happens. For all of their power, the Mapper XML files are relatively simple. Certainly if you were to compare them to the equivalent JDBC code, you would immediately see a savings of 95% of the code. MyBatis was built to focus on the SQL, and does its best to stay out of your way.

The Mapper XML files have only a few first class elements (in the order that they should be defined):

• cache – Configuration of the cache for a given namespace.
• cache-ref – Reference to a cache configuration from another namespace.
• resultMap – The most complicated and powerful element that describes how to load your objects from the database result sets.
• parameterMap – Deprecated! Old-school way to map parameters. Inline parameters are preferred and this element may be removed in the future. Not documented here.
• sql – A reusable chunk of SQL that can be referenced by other statements.
• insert – A mapped INSERT statement.
• update – A mapped UPDATE statement.
• delete – A mapped DELETE statement.
• select – A mapped SELECT statement.

The next sections will describe each of these elements in detail, starting with the statements themselves.

• select
• insert, update and delete
• sql
• Parameters
• Result Maps
• Auto-mapping
• cache