mybatis parameterMap

MyBatis provides the `parameterMap` element as a way to map complex parameter objects to the SQL statement parameters. It is used when you have a complex object with multiple properties and you want to map them to the corresponding parameters in your SQL statement.

To use the `parameterMap`, you need to define it in your MyBatis XML configuration file. Here's an example:

<!-- Define the parameterMap -->
<parameterMap id="myParameterMap" type="com.example.MyParameterObject">
  <parameter property="param1" jdbcType="VARCHAR"/>
  <parameter property="param2" jdbcType="INTEGER"/>
  <!-- more parameters... -->
</parameterMap>

<!-- Use the parameterMap in your SQL statement -->
<select id="myQuery" parameterMap="myParameterMap">
  SELECT * FROM my_table
  WHERE column1 = #{param1}
  AND column2 = #{param2}
  <!-- more conditions... -->
</select>

In the above example, `com.example.MyParameterObject` is a Java class representing the complex parameter object. The `parameterMap` element defines the mappings between the properties of `MyParameterObject` and the SQL statement parameters. Each `parameter` element specifies the property name and the corresponding JDBC type.

You can then reference the `parameterMap` in your SQL statement using the `parameterMap` attribute of the statement. The `#{param1}` and `#{param2}` placeholders will be replaced with the values from the corresponding properties of the parameter object.

Note that starting from MyBatis 3, it is recommended to use annotation-based parameter mapping (`@Param` annotation) or inline parameter mapping (`#{property}`) instead of `parameterMap` for simplicity and better readability.