mybatis插入Oracle主键(自增键)

      在mybatis插件oracle数据库，如果是主键自增型的，就要考虑是已经有触发器处理，还是只有sequence，这样才能在保存后的类里面主键才有值。

1、只有sequence时，demo如下

declare
V_NUM number;
BEGIN
  V_NUM := 0;
  ----判断序列是否存在（区分大小写）
  select count(0) into V_NUM from user_sequences where sequence_name=upper('S_SYS_USER'); 
  ----如果存在立即删除
  if V_NUM > 0 then
    execute immediate 'DROP SEQUENCE S_SYS_USER';
  end if;
END;
/

--创建序号的规则
create sequence S_SYS_USER
  INCREMENT BY 1   -- 每次加几个  
  START WITH 1     -- 从1开始计数  
  NOMAXVALUE       -- 不设置最大值  
  NOCYCLE ;         -- 一直累加，不循环
/

<insert id="save" parameterType="com.bootdo.system.domain.UserDO">
    	<selectKey resultType="long" keyProperty="userId" order="BEFORE"> 
	        SELECT S_SYS_USER.NEXTVAL FROM DUAL 
	    </selectKey> 
		insert into sys_user
		(
			username, 
			name, 
			password, 
		)
		values
		(
			#{username,jdbcType=VARCHAR}, 
			#{name,jdbcType=VARCHAR}, 
			#{password,jdbcType=VARCHAR}
		)
	</insert>

 

2、通过Oracle触发器

declare
V_NUM number;
BEGIN
  V_NUM := 0;
  ----判断序列是否存在（区分大小写）
  select count(0) into V_NUM from user_sequences where sequence_name=upper('S_SYS_USER'); 
  ----如果存在立即删除
  if V_NUM > 0 then
    execute immediate 'DROP SEQUENCE S_SYS_USER';
  end if;
END;
/

--创建序号的规则
create sequence S_SYS_USER
  INCREMENT BY 1   -- 每次加几个  
  START WITH 1     -- 从1开始计数  
  NOMAXVALUE       -- 不设置最大值  
  NOCYCLE ;         -- 一直累加，不循环
/

--创建触发器  DROP TRIGGER TIB_SYS_USER  --删除触发器
create or replace trigger TIB_SYS_USER before insert on SYS_USER for each row
declare
    integrity_error  exception;
    errno            integer;
    errmsg           char(200);
    dummy            integer;
    found            boolean;
begin
    select S_SYS_USER.NEXTVAL INTO :new.user_id from dual;
exception
    when integrity_error then
       raise_application_error(errno, errmsg);
end;

 

<insert id="save" parameterType="com.bootdo.system.domain.UserDO">
    	<selectKey resultType="long" keyProperty="userId" order="AFTER"> 
	        SELECT S_SYS_USER.CURRVAL FROM DUAL 
	    </selectKey> 
		insert into sys_user
		(
			username, 
			name, 
			password
		)
		values
		(
			#{username,jdbcType=VARCHAR}, 
			#{name,jdbcType=VARCHAR}, 
			#{password,jdbcType=VARCHAR}
		)
	</insert>

@Transactional
    @Override
    public int save(UserDO user) {
        int count = userMapper.save(user);
        //这样userid才能有值
        Long userId = user.getUserId();
        return count;
    }