Hibernate @ManyToOne and @OneToMany fetch data as List(num of records)

Question

I have 2 tables
1.Org[ORG_ID,PARENT_ID,LANG_ID(REFERENCES LANG)] 2.Lang[LANG_ID,LANG_NAME]

My JAVA Entity Files

Lang.java

@Entity
@JsonIdentityInfo(generator = ObjectIdGenerators.PropertyGenerator.class, property = "langId")
@JsonIgnoreProperties({ "hibernateLazyInitializer", "handler" })
@SuppressWarnings("serial")
public class Lang implements java.io.Serializable {
    private BigDecimal langId;
    private String langName;
    private Set<Org> orgs = new HashSet<Org>(0);
    public Lang() {
    }
    public Lang(BigDecimal langId, Set<Org> orgs) {
        this.langId = langId;
        this.orgs = orgs;
    }
    public BigDecimal getLangId() {
        return this.langId;
    }
    public void setLangId(BigDecimal langId) {
        this.langId = langId;
    }
    public String getLangName() {
        return this.langName;
    }
    public void setLangName(String langName) {
        this.langName = langName;
    }public void setOrgs(Set<Org> orgs) {
        this.orgs = orgs;
    }
}

Org.java

    @Entity
@JsonIdentityInfo(generator = ObjectIdGenerators.PropertyGenerator.class, property = "orgId")
@JsonIgnoreProperties({ "hibernateLazyInitializer", "handler" })
@SuppressWarnings("serial")
public class Org implements java.io.Serializable {
    @Id
    @Column(name = "orgId")
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private BigDecimal orgId;   
    private BigDecimal parentOrgId;
    @JsonIdentityInfo(generator = ObjectIdGenerators.PropertyGenerator.class, property = "langId",scope=Lang.class)
    public Org() {
    }
    public Org(BigDecimal orgId, BigDecimal parentOrgId, Lang lang) {
        this.orgId = orgId;
        this.parentOrgId = parentOrgId;
        this.lang = lang;
    }
    public BigDecimal getOrgId() {
        return this.orgId;
    }
    public void setOrgId(BigDecimal orgId) {
        this.orgId = orgId;
    }
    public BigDecimal getParentOrgId() {
        return this.parentOrgId;
    }
    public void setParentOrgId(BigDecimal parentOrgId) {
        this.parentOrgId = parentOrgId;
    }
    @ManyToOne(cascade = CascadeType.ALL, fetch = FetchType.EAGER)
    public Lang getLang() {
        return this.lang;
    }
    public void setLang(Lang lang) {
        this.lang = lang;
    }
}

My HBM Xml Files

Org.hbm.xml

    <hibernate-mapping package="com.test.entity">
    <class name="com.test.entity.Org" table="ORG">
    <id name="orgId" type="big_decimal">
        <column name="ORG_ID" precision="22" scale="0" />
        <generator class="increment" />
    </id>        
    <property name="parentOrgId" type="big_decimal">
        <column name="PARENT_ORG_ID" precision="22" scale="0" not-null="true" />
    </property>
    <many-to-one name="lang" class="com.test.entity.Lang" fetch="select">
        <column name="LANG_ID" precision="22" scale="0" not-null="true" />
    </many-to-one>        
    </class>
</hibernate-mapping>

Lang.hbm.xml

    <hibernate-mapping package="com.test.entity">
    <class name="com.test.entity.Lang" table="LANG">
    <id name="langId" type="big_decimal">
        <column name="LANG_ID" precision="22" scale="0" />
        <generator class="increment" />
    </id>
    <property name="langName" type="string">
        <column name="LANG_NAME" length="32" not-null="true" unique="true" />
    </property>
    <set name="orgs" table="ORG" inverse="true" lazy="true" fetch="select">
        <key>
        <column name="LANG_ID" precision="22" scale="0" not-null="true" />
        </key>
        <one-to-many class="com.test.entity.Org" />
    </set>
    </class>
</hibernate-mapping>

My Hibernate Query is : "FROM Org as org WHERE org.parentOrgId = :parentOrgId or org.orgId=:parentOrgId"
Image of DataBase
When I run from controller List listOrganization = organizationService.getAllChildWithParetOrgs(parentId);//parentId = 0

I got result ObjectList/JSON Result is

    [
  {
    "orgId": 1,
    "parentOrgId": 0,    
    "lang": {
      "langId": 1,
      "langName": "EN",
      "orgs": [
    {
      "orgId": 2,
      "parentOrgId": 1,
      "lang": 1,
      "currency": {
        "currencyId": 1,
        "currencyCode": "INR",
        "currencyName": "INR",
        "currencyDescription": "INDIAN RUPEE",
        "orgs": [
          2,
          1,
          {
        "orgId": 3,
        "parentOrgId": 1,
        "lang": 1,
        "currency": 1,                
          }
        ]
      }
    },
    1,
    3
      ]
    },
    "currency": 1
  },
  2, //---> Here No 2nd Organization Data
  3  //---> Here No 3rd Organization Data
]

Here Currency also same as Lang table Its Currency_Id reference to Currency
am not able to get 2nd & 3rd Org data in Array,it is Available in Lang.Orgs and Lang.Orgs.Currency
Please help on this.Thanks.

score 0 · Answer 1 · answered Aug 16 '16 at 10:38

This will get you started, I am using Spring JPA2 with Hibernate, and Jackson.

I let Hibernate create my tables from entities.

Spring application context looks like this:

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:jdbc="http://www.springframework.org/schema/jdbc"
    xmlns:jpa="http://www.springframework.org/schema/data/jpa" xmlns:tx="http://www.springframework.org/schema/tx"
    xmlns:context="http://www.springframework.org/schema/context"
    xmlns:cache="http://www.springframework.org/schema/cache"
    xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
    http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx.xsd
    http://www.springframework.org/schema/jdbc http://www.springframework.org/schema/jdbc/spring-jdbc.xsd
    http://www.springframework.org/schema/data/jpa http://www.springframework.org/schema/data/jpa/spring-jpa.xsd
    http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd
    http://www.springframework.org/schema/cache http://www.springframework.org/schema/cache/spring-cache.xsd">

    <context:component-scan base-package="com.greg" />
    <tx:annotation-driven />
    <jpa:repositories base-package="com.greg.repository" />

    <bean id="dataSource"
        class="org.springframework.jdbc.datasource.DriverManagerDataSource">
        <property name="driverClassName" value="org.h2.Driver" />
        <property name="url" value="jdbc:h2:mem:test;DB_CLOSE_DELAY=-1" />
        <property name="username" value="sa" />
        <property name="password" value="" />
    </bean>

    <bean id="entityManagerFactory"
        class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
        <property name="dataSource" ref="dataSource" />
        <property name="packagesToScan" value="com.greg.entity" />
        <property name="jpaVendorAdapter">
            <bean class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter" />
        </property>
        <property name="jpaProperties">
            <props>
                <prop key="hibernate.hbm2ddl.auto">create</prop>
                <prop key="hibernate.show_sql">false</prop>
                <prop key="hibernate.format_sql">false</prop>
                <prop key="hibernate.dialect">org.hibernate.dialect.H2Dialect</prop>
            </props>
        </property>
    </bean>

    <bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager">
        <property name="entityManagerFactory" ref="entityManagerFactory" />
    </bean>

</beans>

Lang entity looks like this :

@Entity
public class Lang {

    @Id
    @Column(name = "lang_id")
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Long langId;

    @Column(name = "lang_name")
    private String langName;

    @OneToMany(fetch = FetchType.EAGER)
    @JoinColumn(name = "lang_id", referencedColumnName = "lang_id")
    private Set<Org> orgs;

Org entity looks like this :

@Entity
public class Org {

    @Id
    @Column(name = "org_id")
    @GeneratedValue(strategy = GenerationType.AUTO)
    private Long orgId;

    @ManyToOne(fetch = FetchType.EAGER)
    @JoinColumn(name = "lang_id", referencedColumnName = "lang_id", updatable = false, insertable = false, nullable = false)
    private Lang lang;

    @ManyToOne(fetch = FetchType.EAGER)
    @JoinColumn(name = "parent_id", referencedColumnName = "org_id", updatable = false, insertable = false, nullable = false)
    private Org parent;

This create the tables in your question.

Spring JPA repositories are simple :

@Repository
@Transactional
public interface OrgRepository extends CrudRepository<Org, Long> {
}

and

@Repository
@Transactional
public interface OrgRepository extends CrudRepository<Lang, Long> {
}

If I let Jackson serialize I get :

    {
    "orgId": 4,
    "lang": {
        "langId": 1,
        "langName": "EN",
        "orgs": null
    },
    "parent": {
        "orgId": 3,
        "lang": {
            "langId": 1,
            "langName": "EN",
            "orgs": null
        },
        "parent": {
            "orgId": 2,
            "lang": {
                "langId": 1,
                "langName": "EN",
                "orgs": null
            },
            "parent": null
        }
    }
}

My test is :

    @Test
@Transactional
public void test1() {

    try {
        Lang lang = makeLang("EN");
        langRepository.save(lang);
        assertNotNull(lang.getLangId());

        Org org1 = new Org();
        org1.setLang(lang);
        orgRepository.save(org1);

        Org org2 = new Org();
        org2.setLang(lang);
        org2.setParent(org1);
        orgRepository.save(org2);

        Org org3 = new Org();
        org3.setLang(lang);
        org3.setParent(org2);
        orgRepository.save(org3);

        assertEquals("EN", orgRepository.findOne(org1.getOrgId()).getLang().getLangName());
        assertNull(orgRepository.findOne(org1.getOrgId()).getParent());

        assertEquals("EN", orgRepository.findOne(org2.getOrgId()).getLang().getLangName());
        assertEquals(org1.getOrgId().longValue(), orgRepository.findOne(org2.getOrgId()).getParent().getOrgId().longValue());

        assertEquals("EN", orgRepository.findOne(org3.getOrgId()).getLang().getLangName());
        assertEquals(org2.getOrgId().longValue(), orgRepository.findOne(org3.getOrgId()).getParent().getOrgId().longValue());

        System.out.println(new ObjectMapper().writeValueAsString(org3));

        showTables("ORG");
        showTables("LANG");
    } catch (Exception e) {
        e.printStackTrace();
        fail();
    }
}

private Lang makeLang(String name) {
    Lang lang = new Lang();
    lang.setLangName(name);
    return lang;
}

score 0 · Answer 2 · answered Aug 22 '16 at 10:09

Please provide the code of your Controller method getAllChildWithParetOrgs(parentId);. That will be more helpful. Also, as per my understanding from the hibernate query joins and database snapshots, I don't think JSON output should enlist anymore records. Please find the explanation below:

As the parentId which you've passed is 0. And based on the hibernate query joins and the database snapshots, it seems that there is no individual record for OrgId = 0. And from parentOrgId = 0 part of the clause, it is referring to the child: the record which has orgId as 1. Subsequently, it is referring to the child records for orgId = 1, that is, the records with parentOrgId = 1 which are the records: orgId = 2 & orgId = 3. I dont think your JSON object should enlist any more results after that

Hibernate @ManyToOne and @OneToMany fetch data as List(num of records)

2 Answers2