Hibernate mapping parsing--correlation mapping (III)

The following is an introduction to hibernate, another way of associating mappings.

There are two implementation strategies for one-to-single affinity mappings: primary key affinity mappings and unique foreign Key association mappings.

PRIMARY KEY affinity mapping: Let two objects have the same primary key value to justify the one by one correspondence between them; The database table does not have additional fields to maintain the relationship between them, and is only associated with the primary key of the table.

1. One-to-one primary key association:

Object Model:

Relational Model:

IdCard.hbm.xml

<?xml version= "1.0"? ><! DOCTYPE hibernate-mapping Public "-//hibernate/hibernate mapping DTD 3.0//en" "http://hibernate.sourceforge.net/ Hibernate-mapping-3.0.dtd ">

Person.hbm.xml
<?xml version= "1.0"? ><! DOCTYPE hibernate-mapping Public "-//hibernate/hibernate mapping DTD 3.0//en" "http://hibernate.sourceforge.net/ Hibernate-mapping-3.0.dtd ">

2. Bidirectional one-to-one correlation

Object Model:

Relational Model:


IdCard.hbm.xml
<?xml version= "1.0"? ><! DOCTYPE hibernate-mapping Public "-//hibernate/hibernate mapping DTD 3.0//en" "http://hibernate.sourceforge.net/ Hibernate-mapping-3.0.dtd ">


Person.hbm.xml
<?xml version= "1.0"? ><! DOCTYPE hibernate-mapping Public "-//hibernate/hibernate mapping DTD 3.0//en" "http://hibernate.sourceforge.net/ Hibernate-mapping-3.0.dtd ">

The difference between a one-way and a-way is that two-way Idcard joins the <one-to-one> tag, indicating that hibernate will load the associated object on the primary key,<one-to-one> does not affect the storage. only affects loading.

Next article: one-to-one the second mapping method is the unique foreign Key association.
Hibernate mapping parsing--correlation mapping (III)