I have 3 entities:
@Entity
class A
{
@Id @GeneratedValue(strategy = GenerationType.SEQUENCE)
Long id
@Basic
String name
@OneToMany(mappedBy = "a", fetch = FetchType.EAGER, cascade =
[CascadeType.ALL])
List<B> bs = []
}
@Entity
class B
{
@Id @GeneratedValue(strategy = GenerationType.SEQUENCE)
Long id
@Basic
String name
@ManyToOne(cascade = [CascadeType.PERSIST, CascadeType.MERGE,
CascadeType.DETACH])
A a
@OneToMany(mappedBy = "b", fetch = FetchType.EAGER, cascade =
[CascadeType.ALL])
List<C> cs = []
void setA(A a)
{
if(this.a != null)
{
this.a.getBs().remove(this)
}
if(a != null)
{
a.getBs().add(this)
}
this.a = a
}
}
@Entity
class C
{
@Id @GeneratedValue(strategy = GenerationType.SEQUENCE)
Long id
@Basic
String name
@ManyToOne(cascade = [CascadeType.PERSIST, CascadeType.MERGE,
CascadeType.DETACH])
B b
void setB(B b)
{
if(this.b != null)
{
this.b.getCs().remove(this)
}
if(b != null)
{
b.getCs().add(this)
}
this.b = b
}
}
A and B has OneToMany relations. Both relations defined by fetch =
FetchType.EAGER.
in persistence.xml
<property name="openjpa.jdbc.EagerFetchMode"
value="join"/>
Therefore, whe I do em.find(A.class, id), it produces several sqls instead of
one:
SELECT t0.NAME, t1.A_ID, t1.ID, t1.NAME
FROM APP.A t0 LEFT OUTER JOIN APP.B t1 ON t0.ID = t1.A_ID
WHERE t0.ID = ?
ORDER BY t1.A_ID ASC
[params=(long) 1]
5921 openjpa-examples TRACE [main] openjpa.jdbc.SQL - <t 1132441875, conn
1170789081> [6 ms] spent
5952 openjpa-examples TRACE [main] openjpa.jdbc.SQL - <t 1132441875, conn
1170789081> executing prepstmnt 636562801
SELECT t0.ID, t0.NAME
FROM APP.C t0
WHERE t0.B_ID = ?
[params=(long) 52]
5953 openjpa-examples TRACE [main] openjpa.jdbc.SQL - <t 1132441875, conn
1170789081> [1 ms] spent
5957 openjpa-examples TRACE [main] openjpa.jdbc.SQL - <t 1132441875, conn
1170789081> executing prepstmnt 745129193
SELECT t0.ID, t0.NAME
FROM APP.C t0
WHERE t0.B_ID = ?
[params=(long) 51]
How to select A and eager fetch B and Bs Cs field?
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