Returning values from MyBatis mapped methods

Question

I have a Java project that uses MyBatis to access a PostgreSQL database. PostgreSQL allows to return fields of a newly created row after an INSERT statement, an

Answer 1

There are two ways (at least that I know) to get the ID of the one inserted record:

For example, we have a class EntityDao:

public class EntityDao {
     private Long id;
     private String name;
     // other fields, getters and setters
}

---

1. Using the insert tag and returning an instance of object

MyBatis interface

public interface EntityDaoMapper {
    EntityDao insert(EntityDao entity);
}

MyBatis XML mapper:

    INSERT INTO some_table (name, type, other_fields, etc)
    VALUES (#{name}, #{type}, #{other_fields}, #{etc}) 

Sample code:

    EntityDao saved = entityDaoMapper.insert(entityToSave);
    System.out.println(saved.getId());

2. Using select and resultType tags to return the ID of the record only

MyBatis interface

public interface EntityDaoMapper {
    Long insert(EntityDao entity);
}

MyBatis XML mapper:

    INSERT INTO some_table (name, type, other_fields, etc)
    VALUES (#{name}, #{type}, #{other_fields}, #{etc}) 
    RETURNING entity_id       <-- id only or many fields

Sample code:

Long id = entityDaoMapper.insert(entityToSave);
System.out.println(id);