Problems using mybatis to insert statements based on ID auto-increment?
Resolved in mybatis core configuration file
MYSQL solution:
<!-- public void addDept(Dept dept);
MySQL supports self-incrementing primary keys; to obtain self-incrementing primary keys, mybatis also uses statement.getGeneratedKeys()
To get the added number in the foreground, add two properties
useGeneratedKeys="true": Use the auto-incrementing primary key to get the primary key value
keyProperty: The corresponding primary key property, that is, after mybatis gets the primary key value, which property of javaBean will this value be encapsulated to
-->
<insert id="addDept" useGeneratedKeys="true" keyProperty="deptno" databaseId="mysql" >
insert into dept(dname,loc) values (#{dname},#{loc});
</insert>
Oracle solution:
<!--Oracle does not support auto-increment; Oracle uses sequence sequences to simulate auto-increment;
The primary key of the data inserted each time is the value obtained from the sequence: if the song gets this value?
-->
<insert id="addDept" databaseId="oracle" >
<!-- keyProperty: Which property of the JavaBean the detected primary key is encapsulated to
order="BEFORE": the current SQL is run before insert
AFTER: The current SQL is run after the insert
resultType: find out the return value type of the data
BEFORE running order:
First run selectKey to query id's sql; find out that the value of id is encapsulated to the id attribute of javaBean
Then run the inserted SQL; you can take out the value corresponding to the id attribute
AFTER：
Run the inserted SQL first (take the new value from the sequence as id)
Then run the selectKey query id sql
-->
<selectKey keyProperty="deptno" order="BEFORE" resultType="Integer">
<!-- Write a SQL statement to query the primary key-->
<!-- BEFORE：-->
SELECT seq_deptno.nextval FROM dual
<!-- AFTER:
SELECT seq_deptno.currval FROM dual
-->
</selectKey>
<!-- The primary key when inserting is taken from the sequence -->
<!-- BEFORE： -->
insert into dept(deptno,dname,loc)
values (#{deptno},#{dname},#{loc})
<!-- AFTER:
insert into dept(deptno,dname,loc)
values (seq_deptno.nextval,#{dname},#{loc})
-->
</insert>