EJB3.x：关于@UniqueConstraint标记中的columnNames属性

EJB3.x：关于@UniqueConstraint标记中的columnNames属性

例如以下代码：

package net.model.entity;

import java.io.Serializable;

import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.GenerationType;
import javax.persistence.Id;
import javax.persistence.Table;
import javax.persistence.UniqueConstraint;

@Entity
@Table(
		name="ROLE" ,
		uniqueConstraints={@UniqueConstraint(columnNames={"ROLE_NAME"})}				
)
public class Role implements Serializable
{
	private Integer id ;
	
	private String roleName;
	
	private int roleValue ;
	


	@Id
	@GeneratedValue(strategy=GenerationType.AUTO)
	@Column(name="ROLE_ID")
	public Integer getId() {
		return id;
	}

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

	
	
	@Column(name="ROLE_NAME" , nullable=false ,length=50)
	public String getRoleName() {
		return roleName;
	}

	public void setRoleName(String roleName) {
		this.roleName = roleName;
	}

	@Column(name="ROLE_VALUE" , nullable=false)
	public int getRoleValue() {
		return roleValue;
	}

	public void setRoleValue(int roleValue) {
		this.roleValue = roleValue;
	}

}

注意uniqueConstraints={@UniqueConstraint(columnNames={"ROLE_NAME"})}中的columnNames属性值为数据库表中的字段名，而不是Role类中的类成员名roleName。