backend/src/main/java/nju/seec/helper/entity/Course.java

package nju.seec.helper.entity;

import lombok.Data;
import lombok.experimental.Accessors;
import org.hibernate.annotations.CreationTimestamp;
import org.hibernate.annotations.DynamicInsert;
import org.hibernate.annotations.DynamicUpdate;

import javax.persistence.*;
import java.time.LocalDateTime;

/**
 * @author cst
 */
@Data
@Accessors(chain = true)
@Entity
@Table(name = "course",
        uniqueConstraints = @UniqueConstraint(name = "course_name_constraint", columnNames = {"teacher_id", "delete_at", "name"}))
@DynamicUpdate
@DynamicInsert
public class Course {
    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;

    @Column(nullable = false)
    private String name;

    @Column(nullable = false)
    private String bio;

    @Column(nullable = false)
    private String code;

    @Column(name = "create_at", nullable = false, updatable = false)
    @CreationTimestamp
    private LocalDateTime createAt;

    @ManyToOne(cascade = {CascadeType.DETACH, CascadeType.MERGE, CascadeType.REFRESH}, fetch = FetchType.LAZY)
    @JoinColumn(name = "teacher_id", nullable = false)
    private User teacher;

    @Column(name = "delete_at", columnDefinition = "bigint default 0 not null")
    private Long deleteAt = 0L;
}