what is an entity in hibernate?
Entity: In general entity is an object that has some distinct value. In a persistent storage mechanism, an entity is a business object. Each entity has an associated table in relational database. Each instance of the entity represents a row of the table.
Entity class is an annotated POJO (Plain Old java Object). Here are some points to be noted during writing entity class:
· Class must have constructor
· Create getter setter for each field
· Don?t define any field static or final.
Example:
Here is an entity class named Employee.java.It mapped the employee table.
package net.roseindia.table; import javax.persistence.Column; import javax.persistence.Entity; import javax.persistence.GeneratedValue; import javax.persistence.Id; import javax.persistence.Table; import java.util.Date; @Entity @Table(name = "employee") public class Employee { @Id @GeneratedValue @Column(name = "emp_id") private int id; @Column(name = "name") private String name; @Column(name = "salary") private int salary; @Column(name = "date_of_join") private Date dateOfJoin; public int getId() { return id; } public void setId(int id) { this.id = id; } public String getName() { return name; } public void setName(String name) { this.name = name; } public int getSalary() { return salary; } public void setSalary(int salary) { this.salary = salary; } public Date getDateOfJoin() { return dateOfJoin; } public void setDateOfJoin(Date dateOfJoin) { this.dateOfJoin = dateOfJoin; } }
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