表字段設定預設值

• 記錄意義：學習記錄
• 方法一：使用@Column註解中的columnDefinition屬性設定預設值
  • 程式碼如下

@Entity
@Table(name = "m_test")
@DynamicInsert
@DynamicUpdate
public class TestTable implements Serializable {

    private static final long serialVersionUID = 1L;

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name 
 
= "id", columnDefinition = "BIGINT")
    private Long id;

    @Column(name = "user_name", columnDefinition = "varchar(50) NOT NULL COMMENT '使用者名稱稱'")
    private String userName;

    @Column(name = "address", columnDefinition = "varchar(50) NOT NULL COMMENT '使用者地址'")
    private String address;
    
    @Column(name 
 
= "sex", columnDefinition = "tinyint NOT NULL DEFAULT 0 COMMENT '性別：0-男  1-女'")
    private Integer sex;

}

• • 注意：在使用這個方法設定欄位預設值時，如果定義了NOT NULL，則要在使用類註解@DynamicInsert和@DynamicUpdate，否則報錯

• 方法二：直接為類屬性設定值
  • 程式碼如下

@Entity
@Table(name = "m_test")
public class TestTable implements Serializable {

    
 
private static final long serialVersionUID = 1L;

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "id", columnDefinition = "BIGINT")
    private Long id;

    @Column(name = "user_name", columnDefinition = "varchar(50) NOT NULL COMMENT '使用者名稱稱'")
    private String userName;
    
    @Column(name = "address", columnDefinition = "varchar(50) NOT NULL COMMENT '使用者地址'")
    private String address;
    
    @Column(name = "sex", columnDefinition = "tinyint NOT NULL'")
    private Integer sex = 0;

}

• 建議：使用方法二

時間型別

• 記錄意義：在資料庫設定時間型別時，有的使用timestamp ，有的使用datetime，個人推薦使用datetime
• 程式碼如下

@Entity
@Table(name = "m_test")
public class TestTable implements Serializable {

    private static final long serialVersionUID = 1L;

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    @Column(name = "id", columnDefinition = "BIGINT")
    private Long id;

    @Column(name = "user_name", columnDefinition = "varchar(50) NOT NULL COMMENT '使用者名稱稱'")
    private String userName;
    
    @Column(name = "address", columnDefinition = "varchar(50) NOT NULL COMMENT '使用者地址'")
    private String address;
    
    @Column(name = "sex", columnDefinition = "tinyint NOT NULL'")
    private Integer sex = 0;

    @JsonFormat
    @Column(name = "cdate", columnDefinition = "DATETIME DEFAULT CURRENT_TIMESTAMP ")
    private LocalDateTime cdate = LocalDateTime.now();

    @JsonFormat
    @Column(name = "mdate", columnDefinition = "DATETIME DEFAULT CURRENT_TIMESTAMP ")
    private LocalDateTime mdate = LocalDateTime.now();

}