Skip to main content

@AttributeOverrides annotation in hibernate/JPA

@AttributeOverrides annotation is used in hibernate/JPA to rename the column(s) name of the embadable class while it is being embedded in other class.
Suppose A class is embedded in class B, then if A entity contains the column name of any property "phone", then B entity can override the column name to "mobileNumber". So, in the table, column name will be "mobileNumber".

package entity;

import java.io.Serializable;

import javax.persistence.Column;
import javax.persistence.Embeddable;

@Embeddable
public class ContactKey implements Serializable {
    private int roll;
    private String sem;
    private String branch;

    public int getRoll() {
        return roll;
    }

    public void setRoll(int roll) {
        this.roll = roll;
    }

    @Column(name = "sem")
    public String getSem() {
        return sem;
    }

    public void setSem(String sem) {
        this.sem = sem;
    }

    public String getBranch() {
        return branch;
    }

    public void setBranch(String branch) {
        this.branch = branch;
    }

    @Override
    public String toString() {
        return "ContactKey [roll=" + roll + ", sem=" + sem + ", branch="
                + branch + "]";
    }
}


package entity;

import javax.persistence.AttributeOverride;
import javax.persistence.AttributeOverrides;
import javax.persistence.CascadeType;
import javax.persistence.Column;
import javax.persistence.Embedded;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.OneToOne;
import javax.persistence.SequenceGenerator;
import javax.persistence.Table;

@Entity(name="Contact")
@Table(name="Contact")
public class Contact {
    
    @Id
    @GeneratedValue
    private    int id;
    
    @Embedded
    @AttributeOverrides(
            @AttributeOverride(name="sem",column=@Column(name="semester"))
    )
    private ContactKey contactKey;
    private String name;
    private String email;
    private long phone;
    
    
    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getEmail() {
        return email;
    }

    public void setEmail(String email) {
        this.email = email;
    }

    public long getPhone() {
        return phone;
    }
    
    public void setPhone(long phone) {
        this.phone = phone;
    }
    
    public ContactKey getContactKey() {
        return contactKey;
    }

    public void setContactKey(ContactKey contactKey) {
        this.contactKey = contactKey;
    }

    public int getId() {
        return id;
    }

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

here, database table will not contain the column "sem". It will have the "semester" column since we have overridden in contact entity.

Comments

Popular posts from this blog

Using HyperSQL (HSQLDB)

HSQLDB is a portable RDBMS implemented in pure java. It can be embedded with your application as well as can be used separately. It is very a small database that supports almost all features of the standard database system. It comes with small jar file that can be found in lib folder. The HSQLDB jar package is located in the /lib directory of the ZIP package and contains several components and programs. Core components of jar file are : HyperSQL RDBMS Engine (HSQLDB), HyperSQL JDBC Driver, Database Manager, and Sql Tool. Installing and Using Download: download latest release of HyperSQL database from http://hsqldb.org website and extract it. You will see following contents. Here "bin" directory contains some batch files those can be used to run a swing based GUI tool. You can use runManagerSwing.bat to connect to database, but database must be on before running it. Directory lib contains File hsqldb.jar . It is the database to be used by you. Running database First

How to handle values from dynamically generated elements in web page using struts2

Some time you will see the form containing the button " Add More " . This facility is provided for the user to get the values for unknown number of repeating for some information. for example when you are asking to get the projects details from user, you need to put the option to add the more project for the user since you don't known how many projects user have. In the HTML form, you repeat the particular section to get the multiple values for those elements. In Html page , you can put the option to add new row of elements or text fields by writing the java script or using JQuery API. Now, the question is that how to capture the values of dynamically generated text fields on the server. Using the servlet programming you can get the values by using getParameters() method that resultants the array of the parameter having the same name. But this limit you to naming the text fields in the HTML form. To ally this approach, you have to take the same name for t

Generating JTable from database table

package  process; import  javax.swing. * ; import  javax.swing.table. * ; import  java.sql. * ; /**  * This class create JTable from Database table.  * User program needs to specify database connection and corresponding atable name.  * @author Hemraj  */ public   class  TableToJTable {      //private String table;      private   Connection  con;      public   TableToJTable ( Connection  con ){          this .con = con;      }      /**      * This method return JTable object created from Database table having same data asn structure      * as in original table into database.      * @param table Name of the database table to be coverted to JTable      * @return JTable object that consist of data and structure of Database table      * @throws java.lang.Exception Original object is deferent, e.i either SQLException or NullPointerException      */      public   JTable   getTable ( String  table ) throws   Exception {          JTable  t1 = new   JTable () ;          D