Mybatis series (7) --- insert, update, delete of mapper mapping file configuration

Mybatis series (7) --- insert, update, delete time of mapper mapping file configuration
time 2014-10-27 09:24:00 Blog Garden - Java
original http://www.cnblogs.com/dongying/p/4048828 .html
theme MyBatis database
This article will briefly introduce the configuration and use of insert, update, delete, and will give an in-depth explanation of the source code of mybatis in the future.

I believe that when we see insert, update, delete, we will know its function. As the name suggests, myabtis, as a persistence layer framework, must be CRUD-friendly.

Well, let's take a look at how to configure insert, update, delete, and what elements can be configured:

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
PUBLIC "-//ibatis .apache.org//DTD Mapper 3.0//EN"
"http://ibatis.apache.org/dtd/ibatis-3-mapper.dtd">


<mapper namespace="com.dy.dao.UserDao">

    <

        id is a unique identifier in the namespace that can be used to represent this statement.
        A namespace (namespace) corresponds to a dao interface, and
        this id should also correspond to a method in dao (equivalent to the implementation of the method), so the id should be consistent with the method name -->

      id="insertUser"

      

      parameterType="com.demo.User"

      

      flushCache="true"

      <! -- 4. statementType (optional configuration, the default configuration is PREPARED)
        One of STATEMENT, PREPARED or CALLABLE. This will make MyBatis use Statement, PreparedStatement or CallableStatement respectively, default value: PREPARED. -->

      statementType="PREPARED"

      

      keyProperty=""

      

      keyColumn=""

      

      useGeneratedKeys="false"

      
      timeout="20">

    <update
      id="updateUser"
      parameterType="com.demo.User"
      flushCache="true"
      statementType="PREPARED"
      timeout="20">

    <delete
      id="deleteUser"
      parameterType= "com.demo.User"
      flushCache="true"

The above is a template configuration, which are necessary configurations and which are based on your actual needs, you can know at a glance.

Next, let's use the demo in the first article "Mybatis Series (1)---Introduction to Mybatis" as an example:

Database (user table):

My project structure:

User.java:

package com.dy.entity;

public class User {

private int id;
private String name;
private String password;
private int age;
private int deleteFlag;

public int getId() {
    return id;
}
public void setId(int id) {
    this.id = id;
}
public String getName() {
    return name;
}
public void setName(String name) {
    this.name = name;
}
public String getPassword() {
    return password;
}
public void setPassword(String password) {
    this.password = password;
}
public int getAge() {
    return age;
}
public void setAge(int age) {
    this.age = age;
}
public int getDeleteFlag() {
    return deleteFlag;
}
public void setDeleteFlag(int deleteFlag) {
    this.deleteFlag = deleteFlag;
}

}
View Code
UserDao.java:

package com.dy.dao;

import com.dy.entity.User;

public interface UserDao {

public void insertUser (User user);

public void updateUser (User user);

public void deleteUser (User user);

}
View Code
userDao.xml:

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
PUBLIC "-//ibatis.apache.org//DTD Mapper 3.0//EN"
"http://ibatis.apache.org/dtd/ibatis-3-mapper.dtd">

<mapper namespace="com.dy.dao.UserDao">

   
   <insert id="insertUser" parameterType="com.dy.entity.User">
       insert into user(id, name, password, age, deleteFlag)
         values(#{id}, #{name}, #{password}, #{age},#{deleteFlag})    
   </insert>


   <update id="updateUser" parameterType="com.dy.entity.User">
       update user set name = #{name}, password = #{password}, age = #{age}, deleteFlag = #{deleteFlag}
         where id = #{id};
   </update>

   
   <delete id="deleteUser" parameterType="com.dy.entity.User">
       delete from user where id = # {id};
   </delete>
</mapper>
View Code
In this way, a simple mapping relationship is established. Carefully observe the above parameterType, "com.dy.entity.User", if the package name is longer, it will be painful to write like this every time. Don't forget the typeAliases (aliases) we talked about earlier, so if you use aliases in this place, isn't it a skill to say goodbye to the long package name that hurts. Okay, let's match the alias, where is it? Of course, it is in the global configuration file of mybatis (my name here is mybatis-conf.xml), don't think it is configured in the configuration file of mapper.

mybatis-conf.xml:

Through package, you can directly specify the name of the package, mybatis will automatically scan the javabeans under the specified package,
and set an alias by default. The default name is: javabean The unqualified class name of the lowercase first letter is used as its alias.
You can also add annotation @Alias to javabean to customize the alias, for example: @Alias(user)
<package name="com.dy.entity"/>
   -->
<typeAlias alias="user" type="com.dy. entity.User"/>
</typeAliases> In
this way, an alias is taken, and we can directly change the above com.dy.entity.User to user. How convenient!

My database here is mysql. I set the primary key id of the user table to grow automatically, and the above code runs normally, then the problem comes (of course, I don’t want to ask which is the best excavator), if I replace it with an oracle database How to do? But oracle does not support id self-growth? How to do? Please see the following:


   <insert id="insertUser" parameterType="com.dy.entity.User">
       
       insert into user(id, name, password, age, deleteFlag)
       values(#{id}, #{name}, #{password}, #{age} , #{deleteFlag})
   </insert>
Similarly, if we want to return the inserted id after data insertion when using mysql, we can also use the selectKey element:


   <insert id="insertUser" parameterType="com.dy.entity.User">
       

    <! -- After mysql inserts data, get the id -->
    <selectKey keyProperty="id" resultType="int" order="AFTER" >
       SELECT LAST_INSERT_ID() as id
       </selectKey>

       insert into user(id, name, password, age, deleteFlag)
       values(#{id}, # {name}, #{password}, #{age}, #{deleteFlag})
   </insert>
Here, let's briefly mention the <selectKey> element node:

<selectKey

keyProperty="id"

resultType="int"

order="BEFORE"

statementType="PREPARED">
Well, this article mainly introduces the configuration and usage of insert, update, delete. The next article will introduce complex select-related configuration and usage. After all these are finished, I will first analyze the entire running process of mybatis according to the source code, and then go deep into the usage of mybatis.

This article ends here!

Attach the demo download address: http://pan.baidu.com/s/1gdtKf5L

can be downloaded if needed.

Mybatis series (7) --- insert, update, delete of mapper mapping file configuration

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