CREATE TABLE more_specialties (
id INTEGER NOT NULL IDENTITY PRIMARY KEY
,name varchar(50)
, specialty_id INTEGER
<!--if is not null,on one-to-many saveing object will encounter error -->
);
why ?see the following debug report:
...
DEBUG - AbstractBatcher.log(366) | getSQL(sql) = insert into more_specialties (name, id) values (?, null)
...
DEBUG - AbstractBatcher.log(366) | getSQL(sql) = update more_specialties set specialty_id=? where id=?...
it is clearly that it first insert null values to the specialty_id the update it.and in business logic, specialty_id should be null
it use the
<set name="moreSpecialties" table="more_specialties" cascade="all">
<key column="specialty_id" />
<one-to-many class="MoreSpecialty" />
</set>
and in the one-class Specialty of one-to-many ,initl the Set,else it will be an error of java.lang.NullPointerException!
private Set moreSpecialties=new HashSet();
posted on 2006-08-28 15:18
R.Zeus 阅读(194)
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