Search code examples
javamysqlsqljoinhibernate-criteria

How to join multiple tables without relationship


This is my 1st project in Java/Hibernate.

I m trying to join two tables but even after searching a lot, I couldn't find the proper solution to achieve what i want.

Let me explain you what i have currently.

I have two entities:

@Entity
@Table(name = "admin")
public class AdminLogin {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private int id;
    private String firstName;
    private String lastName;
    private String username;
    private String password;
    private String status;
    private String userRole;

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getFirstName() {
        return firstName;
    }

    public void setFirstName(String firstName) {
        this.firstName = firstName;
    }

    public String getLastName() {
        return lastName;
    }

    public void setLastName(String lastName) {
        this.lastName = lastName;
    }

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

    public String getStatus() {
        return status;
    }

    public void setStatus(String status) {
        this.status = status;
    }

    public String getUserRole() {
        return userRole;
    }

    public void setUserRole(String userRole) {
        this.userRole = userRole;
    }
}


@Entity
@Table(name = "user_balance_log")
public class UserBalanceLog {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private int id;
    private int userId;
    private int adminId;
    private Float balance;
    private String balanceType;
    private String message;
    @Temporal(javax.persistence.TemporalType.DATE)
    private Date dateCreated;

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public int getUserId() {
        return userId;
    }

    public void setUserId(int userId) {
        this.userId = userId;
    }

    public int getAdminId() {
        return adminId;
    }

    public void setAdminId(int adminId) {
        this.adminId = adminId;
    }

    public Float getBalance() {
        return balance;
    }

    public void setBalance(Float balance) {
        this.balance = balance;
    }

    public String getMessage() {
        return message;
    }

    public void setMessage(String message) {
        this.message = message;
    }

    public Date getDateCreated() {
        return dateCreated;
    }

    public void setDateCreated(Date dateCreated) {
        this.dateCreated = dateCreated;
    }

    public String getBalanceType() {
        return balanceType;
    }

    public void setBalanceType(String balanceType) {
        this.balanceType = balanceType;
    }
}

I want to join the adminId from User Balance Log Entity to Admin Login Entity.

This is what i have currently.

Session session = this.sessionFactory.getCurrentSession();

Criteria criteria = session.createCriteria(UserBalanceLog.class, "ubl");

criteria.setProjection(Projections.projectionList().add(Projections.property("balance"),"balance").add(Projections.property("balanceType"),"balanceType").add(Projections.property("message"),"message").add(Projections.property("dateCreated"),"dateCreated"));
criteria.addOrder(Order.desc("id"));       

if (parameters.get("userId") != null) {
    criteria.add(Restrictions.eq("userId", new Integer(parameters.get("userId"))));
}

if (parameters.get("balanceType") != null) {
    criteria.add(Restrictions.eq("balanceType", parameters.get("balanceType")));
}

if (parameters.get("dateCreated") != null) {
    criteria.add(Restrictions.eq("dateCreated", parameters.get("dateCreated")));
}
List userBalanceList = criteria.list();

Please guide me.

Thanks


Solution

  • Finally i figured it out myself of course with the help/guidance of @vc73.

    This is the updation i had to do in model:

    @Entity
    @Table(name = "user_balance_log")
    public class UserBalanceLog {
    
        @Id
        @GeneratedValue(strategy = GenerationType.IDENTITY)
        private int id;
        private int userId;
    
        @ManyToOne
        @JoinColumn(name="adminId")
        private AdminLogin adminId;
    
        private Float balance;
        private String balanceType;
        private String message;
        @Temporal(javax.persistence.TemporalType.DATE)
        private Date dateCreated;
    
        public int getId() {
            return id;
        }
    
        public void setId(int id) {
            this.id = id;
        }
    
        public int getUserId() {
            return userId;
        }
    
        public void setUserId(int userId) {
            this.userId = userId;
        }
    
        public AdminLogin getAdminId() {
            return adminId;
        }
    
        public void setAdminId(AdminLogin adminId) {
            this.adminId = adminId;
        }
    
        public Float getBalance() {
            return balance;
        }
    
        public void setBalance(Float balance) {
            this.balance = balance;
        }
    
        public String getMessage() {
            return message;
        }
    
        public void setMessage(String message) {
            this.message = message;
        }
    
        public Date getDateCreated() {
            return dateCreated;
        }
    
        public void setDateCreated(Date dateCreated) {
            this.dateCreated = dateCreated;
        }
    
        public String getBalanceType() {
            return balanceType;
        }
    
        public void setBalanceType(String balanceType) {
            this.balanceType = balanceType;
        }
    }
    

    and in the DAO:

    Session session = this.sessionFactory.getCurrentSession();
    
    Criteria criteria = session.createCriteria(UserBalanceLog.class, "ubl");
    criteria.createAlias("ubl.adminId", "a");
    
    criteria.setProjection(Projections.projectionList().add(Projections.property("balance").as("balance")).add(Projections.property("balanceType").as("balanceType")).add(Projections.property("message").as("message")).add(Projections.property("dateCreated").as("dateCreated")).add(Projections.property("a.username").as("username")));
    criteria.addOrder(Order.desc("id"));
    
    if (parameters.get("userId") != null) {
        criteria.add(Restrictions.eq("userId", new Integer(parameters.get("userId"))));
    }
    
    if (parameters.get("balanceType") != null) {
        criteria.add(Restrictions.eq("balanceType", parameters.get("balanceType")));
    }
    
    if (parameters.get("dateCreated") != null) {
        criteria.add(Restrictions.eq("dateCreated", parameters.get("dateCreated")));
    }
    
    criteria.setResultTransformer(Criteria.ALIAS_TO_ENTITY_MAP);
    
    criteria.setFirstResult(start);
    criteria.setMaxResults(Pagination.limitPerPage);
    List userBalanceList = criteria.list();
    

    I hope it will help someone else.