name = "idx_category", columnList = "category"))) class Tree { @Id @GeneratedValue(strategy = GenerationType.AUTO...gmtCreated = Date() var gmtModified = Date() var isDeleted = 0 @Version var version = 0 } GenerationType...* * @see GeneratedValue * * @since Java Persistence 1.0 */ public enum GenerationType { /*
主键配置 @Id @GeneratedValue(strategy = GenerationType.IDENTITY) @Column(name = "cust_id")...private Long custId;//主键 @Id:表示这个注解表示此属性对应数据表中的主键 @GeneratedValue(strategy = GenerationType.IDENTITY...strategy表示此注解使用的策略,可以使用GenerationType.IDENTITY、GenerationType.SEQUENCE、GenerationType.TABLE、GenerationType.AUTO...GenerationType.IDENTITY:底层数据库必须支持自动增长,(类似于mysql的自增) GenerationType.SEQUENCE:底层数据库必须支持序列,(Oracle...) GenerationType.TABLE:jpa提供的一种机制,通过一张数据表的形式帮助完成主键自增 GenerationType.AUTO:程序自动选择合适的主键生成策略
lombok.Builder; import lombok.Data; import javax.persistence.GeneratedValue; import javax.persistence.GenerationType...1.1.1、GenerationType.TABLE:使用表生产主键,即使用另外一张表单独维护主键。...: 主键自增 mysql 中的 auto_increment */ @Id @GeneratedValue(strategy =GenerationType.IDENTITY...) private Long uid; 1.1.4、GenerationType.AUTO:自动创建主键(以上三种策略任选一种) @Table(name = "user_info") public...class UserInfo implements Serializable { /** * 表主键 @Id :表示该字段是表主键 * strategy = GenerationType.AUTO
Users 实体 @Entity @Table(name="t_users") public class Users implements Serializable{ @Id //strategy=GenerationType.IDENTITY...自增长 @GeneratedValue(strategy=GenerationType.IDENTITY) @Column(name="userid") private Integer userid...} } 创建 Roles 实体 @Entity @Table(name="t_roles") public class Roles { @Id @GeneratedValue(strategy=GenerationType.IDENTITY...多方 pojo @Entity @Table(name="t_users") public class Users implements Serializable{ @Id //strategy=GenerationType.IDENTITY...自增长 @GeneratedValue(strategy=GenerationType.IDENTITY) @Column(name="userid") private Integer userid
strategy() default AUTO; String generator() default ""; } 其中GenerationType: public...enum GenerationType{ TABLE, SEQUENCE, IDENTITY, AUTO } JPA提供的四种标准用法为...分别介绍其他三个: 1.SEQUENCE 实体类中的注解 @Id @GeneratedValue(strategy =GenerationType.SEQUENCE,generator="aaa"...2.IDENTITY 主键则由数据库自动维护,使用起来很简单 @Id @GeneratedValue(strategy = GenerationType.IDENTITY) 3、AUTO 默认的配置...@Id @GeneratedValue(strategy = GenerationType.AUTO) 二、hibernate主键策略生成器 hibernate提供多种主键生成策略,有点是类似于
import javax.persistence.FetchType; import javax.persistence.GeneratedValue; import javax.persistence.GenerationType...Table(name = "teacher") @Getter @Setter public class Teacher { @Id @GeneratedValue(strategy = GenerationType.IDENTITY...import javax.persistence.FetchType; import javax.persistence.GeneratedValue; import javax.persistence.GenerationType...name = "student") @Getter @Setter public class Student { @Id @GeneratedValue(strategy = GenerationType.IDENTITY...import javax.persistence.FetchType; import javax.persistence.GeneratedValue; import javax.persistence.GenerationType
import javax.persistence.Entity; import javax.persistence.GeneratedValue; import javax.persistence.GenerationType...Table(name = "users") public class Users implements Serializable { @Id @GeneratedValue(strategy = GenerationType.AUTO...import javax.persistence.Entity; import javax.persistence.GeneratedValue; import javax.persistence.GenerationType...import javax.persistence.Entity; import javax.persistence.GeneratedValue; import javax.persistence.GenerationType...import javax.persistence.Entity; import javax.persistence.GeneratedValue; import javax.persistence.GenerationType
import javax.persistence.Entity; import javax.persistence.GeneratedValue; import javax.persistence.GenerationType...import javax.persistence.Entity; import javax.persistence.GeneratedValue; import javax.persistence.GenerationType...import javax.persistence.Entity; import javax.persistence.GeneratedValue; import javax.persistence.GenerationType...import javax.persistence.Entity; import javax.persistence.GeneratedValue; import javax.persistence.GenerationType...import javax.persistence.Entity; import javax.persistence.GeneratedValue; import javax.persistence.GenerationType
Data @Entity @Table(name = "t_address") public class Address { @Id @GeneratedValue(strategy = GenerationType.IDENTITY...Data @Entity @Table(name = "t_school") public class School { @Id @GeneratedValue(strategy = GenerationType.IDENTITY...Data @Entity @Table(name = "t_address") public class Address { @Id @GeneratedValue(strategy = GenerationType.IDENTITY...Data @Entity @Table(name = "t_school") public class School { @Id @GeneratedValue(strategy = GenerationType.IDENTITY...@Data @Table(name = "t_clazz") @Entity public class Clazz { @Id @GeneratedValue(strategy = GenerationType.IDENTITY
@GeneratedValue(strategy = GenerationType.IDENTITY):该注解指定了主键的生成策略,一般不单独出现,这里指定了主键自增的策略。 ?...例如: @Entity @Table(name = "userInfo") public class UserInfo { @Id @GeneratedValue(strategy = GenerationType.IDENTITY...使用使用@GeneratedValue指定主键的生成策略,通过它的strategy属性来指定具体的主键生成方案,该属性可以取如下几个值: GenerationType.AUTO:hibernate默认为该值...,它指明了hibernate自动根据底层数据库选择适当的生成策略 GenerationType.IDENTITY:适用于MySQL,SQLserver的主键自增长策略 GenerationType.SEQUENCE...:适用于Oracle的子串策略 GenerationType.TABLE:基于辅助表的生成主键策略 如果不是使用Oracle做数据库的话,一般我们会使用IDENTITY作为默认的主键生成策略。
userinfo @Entity @Table(name = "userinfo") public class UserInfo { @Id @GeneratedValue(strategy = GenerationType.IDENTITY...usercode @Entity @Table(name = "code") public class UserCode { @Id @GeneratedValue(strategy = GenerationType.IDENTITY...实体类 @Entity @Table(name = "userinfo") public class UserInfo { @Id @GeneratedValue(strategy = GenerationType.IDENTITY...hobby实体类 @Entity @Table(name = "hobby") public class Hobby { @Id @GeneratedValue(strategy = GenerationType.IDENTITY...实体类 @Entity @Table(name = "userinfo") public class UserInfo { @Id @GeneratedValue(strategy = GenerationType.IDENTITY
import javax.persistence.FetchType; import javax.persistence.GeneratedValue; import javax.persistence.GenerationType...String title; private Set answer; @Id @GeneratedValue(strategy = GenerationType.IDENTITY...import javax.persistence.Entity; import javax.persistence.GeneratedValue; import javax.persistence.GenerationType...User userid;//教师id private Questions question; @Id @GeneratedValue(strategy = GenerationType.IDENTITY
@Entitypublic class One { @Id @GeneratedValue(strategy = GenerationType.IDENTITY) private Long...@Entitypublic class Many { @Id @GeneratedValue(strategy = GenerationType.IDENTITY) private Long...首先,我们创建Author实体类:@Entitypublic class Author { @Id @GeneratedValue(strategy = GenerationType.IDENTITY...构造函数、getter和setter方法}然后,我们创建Book实体类:@Entitypublic class Book { @Id @GeneratedValue(strategy = GenerationType.IDENTITY
具体说明如下: IDENTITY:主键由数据库自动生成(主要是自动增长型) 用法: @Id @GeneratedValue(strategy = GenerationType.IDENTITY...用法: @Id @GeneratedValue(strategy = GenerationType.SEQUENCE,generator="payablemoney_seq")...int allocationSize() default 50; } AUTO:主键由程序控制 @Id @GeneratedValue(strategy = GenerationType.AUTO...) private Long custId; TABLE:使用一个特定的数据库表格来保存主键 用法: @Id @GeneratedValue(strategy = GenerationType.TABLE
AuditingEntityListener.class) public class User { /** * 自增主键 */ @Id @GeneratedValue(strategy = GenerationType.IDENTITY...AuditingEntityListener.class) public class User { /** * 自增主键 */ @Id @GeneratedValue(strategy = GenerationType.IDENTITY...NoArgsConstructor @AllArgsConstructor public class BaseEntity { @Id @GeneratedValue(strategy = GenerationType.IDENTITY
1.将实体类的生成策略修改成GenerationType.IDENTITY 因为表里有 唯一约束 或者 ID不能重复,如果用其他策略会出现ID重复 修改实体类: @Id @GeneratedValue...(strategy = GenerationType.IDENTITY) private Long id; 2.仔细看添加数据是否和数据库结构符合 有可能是设计表时,对某一个字段添加了约束,毕竟有的表是按照
unique = true, columnList = "url"))) open class TechArticle { @Id @GeneratedValue(strategy = GenerationType.IDENTITY....* import javax.persistence.Entity import javax.persistence.GeneratedValue import javax.persistence.GenerationType...import javax.persistence.Id @Entity class TechArticleTag { @Id @GeneratedValue(strategy = GenerationType.IDENTITY
定义暂态属性 主键相关的注解 @id: 指定该属性为主键 @GeneratedValue(strategy=,generator="") : 主键生成策略 Strategy的值 GenerationType.AUTO...GenerationType.INDENTITY - 根据数据库的Identity字段生成,支持DB2、MySQL、 MS、...GenerationType.SEQUENCE - 使用Sequence来决定主键的取值,适合Oracle、DB2等 支持Sequence...GenerationType.TABLE - 使用指定表来决定主键取值,结合@TableGenerator使用。...import javax.persistence.Entity; import javax.persistence.GeneratedValue; import javax.persistence.GenerationType
import javax.persistence.Entity; import javax.persistence.GeneratedValue; import javax.persistence.GenerationType...id", name = "find employee by id") public class Employee { @Id @GeneratedValue(strategy= GenerationType.AUTO
@Column(name = "update_at") @CreatedDate private Timestamp updateAt; } 注意上面的主键生成策略用的是 GenerationType.IDENTITY...中指定了数据库 id 时,db 中没有这条记录时,就插入 id 为指定值的记录;如果存在记录,则更新 要实现上面这个功能,自定义主键 id,那么我们就需要修改一下主键的生成策略了,官方提供了四种 取值 说明 GenerationType.TABLE...使用一个特定的数据库表格来保存主键 GenerationType.SEQUENCE 根据底层数据库的序列来生成主键,条件是数据库支持序列 GenerationType.IDENTITY 主键由数据库自动生成...(主要是自动增长型) GenerationType.AUTO 主键由程序控制 从上面四种生成策略说明中,很明显我们要使用的就是 AUTO 策略了,我们新增一个 PO,并指定保存策略 @Data @DynamicUpdate...} } 具体的主键生成方式也比较简单了,首先是判断 PO 中有没有主键,如果有则直接使用 PO 中的主键值;如果没有,就利用IdentityGenerator策略来生成主键(而这个主键生成策略,正好是GenerationType.IDENTITY
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