Hibernate version: 3.2.4 sp.1
Mapping documents:
Code:
<hibernate-mapping default-access="field" package="hb.test">
<class name="Category" table="CATEGORY" dynamic-insert="true" dynamic-update="true">
<id name="id" column="ID" type="long">
<generator class="native" />
</id>
<property name="name" column="NAME" type="string" />
<bag name="books" cascade="save-update, delete, delete-orphan" inverse="true">
<key column="CATEGORY_ID" />
<one-to-many class="Book" />
</bag>
</class>
</hibernate-mapping>
<hibernate-mapping default-access="field" package="hb.test">
<class name="Book" table="BOOK" dynamic-insert="true" dynamic-update="true" mutable="false">
<id name="id" column="ID" type="long">
<generator class="native" />
</id>
<property name="title" type="string" length="50">
<column name="TITLE" sql-type="char(50)" />
</property>
<many-to-one name="category" class="Category" column="CATEGORY_ID" foreign-key="BOOK_CATEGORY_FK"
not-null="true" />
<list name="chapters" cascade="save-update, delete, delete-orphan">
<key column="BOOK_ID" foreign-key="CHAPTER_BOOK_FK" not-null="true" />
<list-index column="_INDEX" base="1" />
<one-to-many class="Chapter" />
</list>
</class>
</hibernate-mapping>
<hibernate-mapping default-access="field" package="hb.test">
<class name="Chapter" table="CHAPTER" dynamic-insert="true" mutable="false">
<id name="id" column="ID" type="long">
<generator class="native" />
</id>
<property name="title" type="string" length="50">
<column name="TITLE" length="50" sql-type="char(50)" />
</property>
<many-to-one name="book" class="Book" column="BOOK_ID" insert="false" update="false" />
</class>
</hibernate-mapping>
save:
Code:
Transaction tx = session.beginTransaction();
Category category = new Category("super");
Book book = new Book("Forrest Gump");
Chapter chapter = new Chapter("Winston Groom");
book.addChapter(chapter);
category.addBook(book);
session.save(category);
tx.commit();
delete:
Code:
Transaction tx = session.beginTransaction();
Category c = (Category) session.createQuery("from Category c where c.id = 1").list().get(0);
System.out.println("About to execute delete: " + c);
session.delete(c);
tx.commit();
Name and version of the database you are using:MySQL 5.0.41 for Win32
The generated SQL (show_sql=true):This is the log generated by Hibernate when the delete code is executed:
Code:
Hibernate:
/*
from
Category c
where
c.id = 1 */ select
category0_.ID as ID0_,
category0_.NAME as NAME0_
from
test.CATEGORY category0_
where
category0_.ID=1
00:50:56,9265p LongType:172 - returning '1' as column: ID0_
00:50:56,9465p StringType:172 - returning 'super' as column: NAME0_
About to execute delete: [Category: super]
Hibernate:
/* load one-to-many hb.test.Category.books */ select
books0_.CATEGORY_ID as CATEGORY3_1_,
books0_.ID as ID1_,
books0_.ID as ID1_0_,
books0_.TITLE as TITLE1_0_,
books0_.CATEGORY_ID as CATEGORY3_1_0_
from
test.BOOK books0_
where
books0_.CATEGORY_ID=?
00:50:56,9665p LongType:133 - binding '1' to parameter: 1
00:50:56,9765p LongType:172 - returning '1' as column: ID1_0_
00:50:56,9765p StringType:172 - returning 'Forrest Gump' as column: TITLE1_0_
00:50:56,9765p LongType:172 - returning '1' as column: CATEGORY3_1_0_
00:50:56,9765p LongType:172 - returning '1' as column: CATEGORY3_1_
00:50:56,9765p LongType:172 - returning '1' as column: ID1_
Hibernate:
/* load one-to-many hb.test.Book.chapters */ select
chapters0_.BOOK_ID as BOOK3_1_,
chapters0_.ID as ID1_,
chapters0_._INDEX as column4_1_,
chapters0_.ID as ID2_0_,
chapters0_.TITLE as TITLE2_0_,
chapters0_.BOOK_ID as BOOK3_2_0_
from
test.CHAPTER chapters0_
where
chapters0_.BOOK_ID=?
00:50:56,9865p LongType:133 - binding '1' to parameter: 1
00:50:57,0065p LongType:172 - returning '1' as column: ID2_0_
00:50:57,0065p StringType:172 - returning 'Winston Groom' as column: TITLE2_0_
00:50:57,0165p LongType:172 - returning '1' as column: BOOK3_2_0_
00:50:57,0165p LongType:172 - returning '1' as column: BOOK3_1_
00:50:57,0165p LongType:172 - returning '1' as column: ID1_
00:50:57,0165p IntegerType:172 - returning '1' as column: column4_1_
Hibernate:
/* update
hb.test.Book */ update
test.BOOK
set
TITLE=?,
CATEGORY_ID=?
where
ID=?
00:50:57,0365p StringType:133 - binding 'Forrest Gump' to parameter: 1
00:50:57,0365p LongType:133 - binding '1' to parameter: 2
00:50:57,0365p LongType:133 - binding '1' to parameter: 3
Hibernate:
/* update
hb.test.Chapter */ update
test.CHAPTER
set
TITLE=?
where
ID=?
00:50:57,0465p StringType:133 - binding 'Winston Groom' to parameter: 1
00:50:57,0465p LongType:133 - binding '1' to parameter: 2
Hibernate:
/* delete hb.test.Chapter */ delete
from
test.CHAPTER
where
ID=?
00:50:57,0465p LongType:133 - binding '1' to parameter: 1
Hibernate:
/* delete hb.test.Book */ delete
from
test.BOOK
where
ID=?
00:50:57,0865p LongType:133 - binding '1' to parameter: 1
Hibernate:
/* delete hb.test.Category */ delete
from
test.CATEGORY
where
ID=?
00:50:57,0965p LongType:133 - binding '1' to parameter: 1
00:50:57,2165p SessionFactoryImpl:769 - closing
And the question is: why when I delete an object, the selects have to be invoked (is this because Hibernate loads the collection proxies and so on so as to cascade the deletion?)
And why are these two update statements executed? They don't seem to make much sense since I don't change anything, and apart from that the mappings for Book and Chapter say these are immutable classes, and according to the tutorial, no updates should ever be done on such classes. That's going on - did I do something wrong?
Thanks.
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