Hibernate Annotations

From:

Peter Horlock <Peter.Horlock@googlemail.com>

Newsgroups:

comp.lang.java.programmer,de.comp.lang.java

Date:

Mon, 3 Aug 2009 10:07:43 -0700 (PDT)

Message-ID:

<7c4a8b9d-8984-4bb0-8514-54df3abdb7ae@n11g2000yqb.googlegroups.com>

Hi,

I am kinda helpless, trying to get a Hibernate Mapping to work! :-(
I've got a table which has a composite Primary Key (2 values).
One of those 2 values is also a foreign key to another table

Then I got another table, where the composite primary key is a foreign
key.

How can this be done in Hibernate, using Annotations?
Do I always have to design the foreign key constraints, even if I
don't really need them?
(Well, I guess it wouldn't hurt to have all data, but I guess I could
do without, too).

Currently, as I couldn't get it to work, I tried to easiest set up
without mapping
the FK constraints.

@Entity
@IdClass(value = MyPrimaryKey.class)
@Table(name = "MYSCEMA.MYTABLE")
@Cache(usage = CacheConcurrencyStrategy.READ_ONLY)
public class MyTable implements Serializable
{
    @Id
    private MyPrimaryKey id;

    @Column(name = "COLUMN3")
    private String column3;

    @Column(name = "COLUMN4")
    private String column4;

    @Column(name = "COLUMN5")
    private String column5;

[..]
}

@Embeddable
public class MyPrimaryKey implements Serializable
{

    @Column(name = "COMPOSITE_ID1_WHICH_IS_ALSO_A_FK")
    private Long compositeId1;

    @Column(name = "COMPOSITE_ID2")
    private Boolean compositeId2;
[..]
}

@Entity
@Table(name = "MYSCEMA.MYTABLE2")
@Cache(usage = CacheConcurrencyStrategy.READ_WRITE)
public class MyTable2 implements java.io.Serializable
{
    @Id
    @Column(name = "ID")
    private String id;

    @Column(name = "COLUMN1")
    private String column1;

    @Column(name = "COMPOSITE_ID1_WHICH_IS_ALSO_A_FK")
    private Integer compositeId1;

    @Column(name = "COMPOSITE_ID2")
    private Boolean compositeId2;

    @Column(name = "TIME")
    @Temporal(TemporalType.TIMESTAMP)
    private Calendar time;
[..]
}

My Create Statmeents (Oracle) look like this:

CREATE TABLE MYSCHEMA.MYTABLE (
    COMPOSITE_ID1_WHICH_IS_ALSO_A_FK INTEGER NOT NULL,
        COMPOSITE_ID2 NUMBER(1,0) DEFAULT 0 NOT NULL,
    COLUMN3 VARCHAR(200) NOT NULL,
    COLUMN4 VARCHAR(20) NOT NULL,
    COLUMN5 VARCHAR(20) NOT NULL,
    CONSTRAINT CONS1 PRIMARY KEY (COMPOSITE_ID1_WHICH_IS_ALSO_A_FK,
COMPOSITE_ID2),
    CONSTRAINT CONS2 FOREIGN KEY (COMPOSITE_ID1_WHICH_IS_ALSO_A_FK)
REFERENCES MYSCHEMA.MYTABLE3(ID),
    CONSTRAINT CONS3 UNIQUE (COLUMN3),
    CONSTRAINT CONS4 CHECK(COMPOSITE_ID2 IN(1,0) )
) ;

CREATE SEQUENCE MYSCHEMA.MY_SEQ
START WITH 1
INCREMENT BY 1
NOMAXVALUE;

CREATE TABLE MYSCHEMA.MYTABLE2 (
    ID NUMBER NOT NULL,
    COLUMN1 VARCHAR(6) NOT NULL,
    COMPOSITE_ID1_WHICH_IS_ALSO_A_FK NUMBER NOT NULL,
    COMPOSITE_ID2 NUMBER(1,0) NOT NULL,
    TIME TIMESTAMP(0) NULL,
    CONSTRAINT CONS5 PRIMARY KEY (ID),
    CONSTRAINT CONS6 FOREIGN KEY (COMPOSITE_ID1_WHICH_IS_ALSO_A_FK,
COMPOSITE_ID2) REFERENCES MYSCHEMA.MYTABLE
(COMPOSITE_ID1_WHICH_IS_ALSO_A_FK, COMPOSITE_ID2)
) ;

Thanks in advance,

Peter