Mybatis frame 3

review:

1.	多参数查询(@Param,对象)
2.	获取保存主键( select last_insert_id )
3.	动态SQL( if, choose when otherwise, where,set ,trim,foreach )
4.	多表操作(一对一,一对多)

1. Nested queries (focus)
   nested query: multiple table joins query SQL statement, split into multiple queries (single-table queries)
   1.1 one
   case: the user query belongs to all accounts and each account
   1.1.1 distinguish the operating body
   operating body: accounts
   1.1.2 to complete multiple queries
   SQL statement
   
   1.1.3 mapping configuration file
   to configure the mapping file operations on the main body of
   
   1.2-to-many
   case: query all accounts in all users, and each user
   1.2.1 distinguish the operating body
   operating body: user
   1.2.2 multiple queries
   
   1.2.3 mapping configuration file
   
2. Loading strategy
   loading strategy: query time associated with the query object
   is loaded immediately: after the query object, instantly check the associated object (the default configuration)
   delay loading (lazy loading): associated objects, when to use, when to check
   2.1 local configuration

配置到SQL映射文件的关联关系配置上 (association, collection)
fetchType:
	eager
	lazy

2.2 Global disposed
in the core configuration file is loaded globally switch

develop methodologies trigger delay loading of

the principles of 2.3 Internal
internal principle: based on dynamic proxy subclass (generated dynamic proxy object is a subclass of the proxy object)
l is proxy object can not be used final modification

3. caching mechanism
3.1 cache
cache:.. SqlSession level cache with the creation of SqlSession created, with the closure and destruction procedures SqlSession comes, can not uninstall

3.1.1 verify cache

3.2 secondary cache
secondary cache:. SqlSessionFactory level cache (cache level Mapper)

3.2.1 secondary cache configuration

4. Interface objects need to implement serialization
   
5. Global open second-level cache support
   .
6. Declared in the mapping file you want to use secondary cache
   
7. Saving data to the secondary cache, you are required to submit or close sqlSession
   
8. Core Configuration (focus)
   Configuration Item core configuration file: sqlMapConfig
   4.1 the Properties
   in the core configuration file using an external properties profile
   
   4.2 typeAlias
   typeAlias: Set an alias is
   
   4.3 Mappers
   loaded sql mapping files
   
   4.4 Settings
   Global Configuration
   
   4.5 Rights to
   
   4.6 using self defined database connection pool
   4.6.1 coordinate
   
   4.6.2 custom factory
   
   4.6.3
   5. programming annotation
   action: replacing the SQL mapping file xml
   5.1 rule

1.	注解配置到dao接口的方法上
2.	注解中配置sql语句,sql语句的语法和xml映射文件中的语法一致
3.	注解 (@Insert, @Update,@Delete,@Select)

5.2 General Notes (Key)
5.2.1 build environment
package name added to a whole class name dao interface mappers in the core configuration file or set dao interfaces in the form of a package
5.2.2

5.3 mapping relationship

@Results : 声明映射关系配置
     id : 当前映射配置的唯一标识
     value : 接收@Result数组
@Result :
     配置属性和字段的映射关系
     property
     column
     id : boolean参数,表明是否配置主键映射关系(true|false)
         默认值:false
@ResultMap : 引用其他已经存在的映射关系配置
             value=其他Results中id

Result and Results

resultMap

5.4 multi-table notes (understand)
only supports nested queries
5.4.1 one-

5.4.2-many

interview questions

1. Delayed loading strategy
2. Caching
   operations:
   1. Exercise 2 preview the first day of spring.