iBatis-- layer interface provides automatic DAO manipulation functions (Detailed)

iBatis-- layer interface provides automatic DAO manipulation functions (Detailed)

　　When performed when using iBatis persistence layer management, discovery data updates using DAO layer updateByPrimaryKey, updateByPrimaryKeySelective method, the results vary. Because not carefully studied before iBatis framework, it is hereby query related articles collated and recorded automatically generated DAO layer interface provides detailed usage and operation function differences are as follows:

　　iBator generated interface DAO layer provides the following functions:

No.	Method name	parameter	return value	abnormal	effect	Remark
1	countByExample	UserExample example	int	√	Conditional Count
2	deleteByPrimaryKey	Integer	int	√	Press the Delete key primary
3	deleteByExample	UserExample example	int	√	Conditional deletion
4	insert	User record	String/Integer	√	Insert (return value id value)
5	selectByPrimaryKey	Integer	User	√	By primary key query
6	selectByExample	UserExample example	List<?>	√	Query by the conditions
7	selectByExampleWithBLOGs	UserExample example	List<?>	√	Query by the conditions (including BLOB fields)	When the field type data in the table are generated as will be binary.
8	updateByPrimaryKey	User record	int	√	By primary key update
9	updateByPrimaryKeySelective	User record	int	√	Updating the primary key value is not null field
10	updateByExample	User record, UserExample example	int	√	Conditional update
11	updateByExampleSelective	User record, UserExample example	int	√	Conditional Update field value is not null

Detailed:

= UserDAO of UserDAOImpl will  new new  of UserDAOImpl will (SqlMapClientFactory. GetSqlMapClient ());
NOTE :. SqlMapClientFactory getSqlMapClient (): is a self-defined classes and methods aimed at obtaining SqlMapClient.

① selectByPrimaryKey()

User user = userDAO.selectByPrimaryKey(100); 相当于select * from user where id = 100

② selectByExample() 和 selectByExampleWithBLOGs()

UserExample example = new UserExample();
Criteria criteria = example.createCriteria();
criteria.andUsernameEqualTo("joe");
criteria.andUsernameIsNull();
example.setOrderByClause("username asc,email desc");
List<?>list = userDAO.selectByExample(example);
相当于：select * from user where username = 'joe' and username is null order by username asc,email desc

Note: in the file contains a static UserExample.java iBator generated inner class Criteria, there are many ways in Criteria, primarily query the custom SQL statement where.

③ insert()

User user = new User();
user.setId(101);
user.setUsername("test");
user.setPassword("123")
user.setEmail("[email protected]");
userDAO.insert(user);
相当于：insert into user(ID,username,password,email) values(101,'test','123','[email protected]');

 ④ updateByPrimaryKey() 和 updateByPrimaryKeySelective()

User user =new User();
user.setId(101);
user.setUsername("joe");
user.setPassword("joe");
user.setEmail("[email protected]");
userDAO.updateByPrimaryKey(user);
相当于：update user set username='joe',password='joe',email='[email protected]' where id=101

User user = new User();
user.setId(101);
user.setPassword("joe");
userDAO.updateByPrimaryKeySelective(user);
相当于：update user set password='joe' where id=101

⑤ updateByExample() 和 updateByExampleSelective()

UserExample example = new UserExample();
Criteria criteria = example.createCriteria();
criteria.andUsernameEqualTo("joe");
User user = new User();
user.setPassword("123");
userDAO.updateByPrimaryKeySelective(user,example);
相当于：update user set password='123' where username='joe'

⑥ deleteByPrimaryKey()

userDAO.deleteByPrimaryKey(101);  相当于：delete from user where id=101

⑦ deleteByExample()

UserExample example = new UserExample();
Criteria criteria = example.createCriteria();
criteria.andUsernameEqualTo("joe");
userDAO.deleteByExample(example);
相当于：delete from user where username='joe'

⑧ countByExample()

UserExample example = new UserExample();
Criteria criteria = example.createCriteria();
criteria.andUsernameEqualTo("joe");
int count = userDAO.countByExample(example);
相当于：select count(*) from user where username='joe'

 

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