我有桌子,下面是摘录。
package test;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.Table;
import javax.persistence.UniqueConstraint;
@Entity
@Table(uniqueConstraints = { @UniqueConstraint(columnNames = "code")},
name = "coupons")
public class Coupon implements Serializable {
private static final long serialVersionUID = 5534534530153298987L;
@Id
@GeneratedValue
@Column(name = "id")
private long id;
@Column(name = "available_count")
private Integer availableCount = 1;
public Integer getAvailableCount() {
return availableCount;
}
public void setAvailableCount(Integer availableCount) {
this.availableCount = availableCount;
}
}
如何使
availableCount
成为非负约束? 最佳答案
如果您需要实际的数据库约束,并且您的架构是由Hibernate生成的,则可以使用@Check
批注:
@Entity
@Table(uniqueConstraints = { @UniqueConstraint(columnNames = "code")},
name = "coupons")
@Check(constraints = "available_count >= 0")
public class Coupon implements Serializable { ... }