For some reason, <inverse-one-to-one> generates a Set instead of a simple pointer.
I'm a bit surprised it's generating a Set instead of emitting an error message explaining why it must be a <many-to-one>.
Details (nonkey columns elided except for one example in each table):
The table being referenced:
Code:
CREATE TABLE "HF_DI_BVKRIT" (
"BKID" NUMBER(27,0) NOT NULL ENABLE,
"VERSION" NUMBER(18,0) DEFAULT 0 NOT NULL ENABLE,
"BKNAME" VARCHAR2(40) NOT NULL ENABLE
) ;
ALTER TABLE "HF_DI_BVKRIT" ADD CONSTRAINT "HF_DI_BVKRIT_PK"
PRIMARY KEY ("BKID") ENABLE;
The table with the foreign key:
Code:
CREATE TABLE "HF_DI_BVKOPF" (
"BVID" NUMBER(10,0) NOT NULL ENABLE,
"VERSION" NUMBER(18,0) DEFAULT 0 NOT NULL ENABLE,
"BVBKID" NUMBER(27,0) NOT NULL ENABLE,
"BVGPRS" NUMBER(8,2)
) ;
ALTER TABLE "HF_DI_BVKOPF" ADD CONSTRAINT "HF_DI_BVKOPF_PK"
PRIMARY KEY ("BVID") ENABLE;
ALTER TABLE "HF_DI_BVKOPF" ADD CONSTRAINT "HF_DI_BVKOPF_UK"
UNIQUE ("BVBKID") ENABLE;
ALTER TABLE "HF_DI_BVKOPF" ADD CONSTRAINT "HF_DI_BVKOPF_FK_BVKRIT"
FOREIGN KEY ("BVBKID") REFERENCES "HF_DI_BVKRIT" ("BKID") ENABLE;
Relevant section from my hibernate.reveng.xml:
Code:
<table name="HF_DI_BVKOPF">
<column name="VERSION" type="long"></column>
<foreign-key constraint-name="HF_DI_BVKOPF_FK_BVKRIT">
<one-to-one />
<inverse-one-to-one />
</foreign-key>
</table>
This generates the following Java classes:
Code:
public class HfDiBvkrit implements java.io.Serializable {
private BigInteger bkid;
private long version;
private String bkname;
private Set <HfDiBvkopf> hfDiBvkopfs = new HashSet <HfDiBvkopf> (0);
...
}
public class HfDiBvkopf implements java.io.Serializable {
private BigInteger bvid;
private long version;
private HfDiBvkrit hfDiBvkrit;
private BigDecimal bvgprs;
...
}
The problem here is
Set <HfDiBvkopf> hfDiBvkopfs. Having a member here is okay (it's the backlink for
HfDiBvkrit hfDiBvkrit in
HfDiBvkopf), but it should be of type
HfDiBvkopf, not
Set <HfDiBvkopf>.
Note that the unique key on BVBKID makes it impossible for multiple BVKOPF records to reference the same BVKRIT record. I had expected that unique key would make Reveng recognize this as a (weak) one-to-one association.
Oh, and yes, I'm 100% sure that <inverse-one-to-one> generates a
Set.
With
<inverse-one-to-one exclude="true"/>, I don't get the
Set (but no non-
Set backlink either).
Is there already a JIRA entry that the reference docs don't explain the usage of <one-to-one> and <inverse-one-to-one>?
Such as the following information bits (please correct any factual errors im making! - this is my current understanding of what reveng does, if I'm wrong, I have no chance of this ever getting to work):
- Explaining that the foreign key needs to reference a full primary or unique key on the foreign table, else it would be a one-to-many relationship (which would have to be declared on the other table anyway)
- Explaining that the foreign key needs to be unique (PK or just a unique index), else we have a many-to-one relationship and people should use <many-to-one> and <set> instead of <one-to-one> and <inverse-one-to-one>.
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