Java Reference
In-Depth Information
Mapping an entity to multiple tables
The
@SecondaryTables
(plural) and
@SecondaryTable
(singular) annotations al-
low JPA to handle the cases where an entity's data must come from two or more tables.
In some rare situations, this is a very sensible strategy. Let's consider the
User
entity in
tionBazaar decided to store the data across the
USERS
and
USER_PICTURES
tables, as
shown in
figure 9.5
.
Figure 9.5. Storing user data across two tables
This makes excellent sense because the
USER_PICTURES
table stores large binary images
that could significantly slow down queries using the table. The
@Secondary-Table
an-
notation enables you to get entity data from more than one table and is defined as follows:
