Hibernate query/realting multiple tables using criteria or hql

Question

i am a newbie to Hibernate and wanted to implement hibernate criteria or hql to query multiple tables to get the results and i am having problem to do that.. right now i am using native sql in hibernate to accomplish what i require but wanted to try the same with hql/criteria.. Below is the native query which i am using to get the results..

select table1.dmname,table2.polname,table3.path,table4.uidname 
    from table1,table2,table3,table4
    where table3.dmnid = table1.dmnid
    and table3.polid = table2.polid
    and table3.3.uid = table4.uid

below are my entity pojo classes

table 1 :

@Entity
@Table(name = "table1", uniqueConstraints = @UniqueConstraint(columnNames = "dmname"))
        @Cache(usage=CacheConcurrencyStrategy.READ_ONLY,region="domain")
public class table1  {

    private String dmnid;
    private String dmnname;

    @Id
    @Column(name = "dmnid", unique = true, nullable = false)
    public String getDmnid() {
        return this.dmnid;
    }

    public void setDmnid(String dmnid) {
        this.dmnid = dmnid;
    }

    @Column(name = "dmnname", unique = true, nullable = false)
    public String getDmnname() {
        return this.dmnname;
    }

    public void setDmnname(String dmnname) {
        this.dmnname = dmnname;
    }

table 2 :

@Entity
@Table(name = "table2", uniqueConstraints = @UniqueConstraint(columnNames = {
        "dmnname", "polname" }))
public class table2 implements java.io.Serializable {

    private String dmnname;
    private String polid;
    private String polname;

    // getters and setter

table 3:

@Entity
@Table(name = "table3")
public class table3 implements java.io.Serializable {

    private String dmnname;
    private String polid;
    private String uid;
    private String path;

    // getters and setters

table 4:

@Entity
@Table(name = "table4", uniqueConstraints = @UniqueConstraint(columnNames = "uidname"))
public class table4 implements java.io.Serializable {

    private String uid;
    private String uidname;

    // getters and setters

I havent implemented out the mapping between the tables in the pojo classes yet and i am having difficulty in understanding that.. so coming out for any help from the community to save me out.. thanks for looking into this and any help will be much appreciated..

Answer 1

I would suggest you refer to the Hibernate docs here for detailed understanding of associations. http://docs.jboss.org/hibernate/orm/5.2/userguide/html_single/Hibernate_User_Guide.html#associations

Regarding your question on HQL, it would look something like this to convert your native SQL (unless you need any explicit join condition):

  Query query = session.createQuery('from table1 t1,table2 t2,table3 t3,table4 t4
        where t3.dmnid = t1.dmnid
        and t3.polid = t2.polid
        and t3.uid = t4.uid');
  List results = query.list();