@Entity @Table @Table(name="employee",schema="HR",catalog="HR") Table用來定義entity主表的name，catalog，schema…等屬性。 屬性說明：
@Id(主鍵) @GeneratedValue JPA 持續性提供程序管理為實體主鍵提供的唯一標識符資料庫的主鍵生成器類型 @GeneratedValue(stategy=Generation.AUTO| TABLE | SEQUENCE | IDENTITY) id值的獲取方式有四種：TABLE, SEQUENCE, IDENTITY, AUTO。 Oracle和DB2支持SEQUENCE SQL Server和Sybase支持IDENTITY, mysql支持AUTO，所有的資料庫都可以指定為AUTO。 @GeneratedValue(stategy=Generation.AUTO) private int id; @GeneratedValue(stategy=Generation.TABLE) private int id; __________________________________________ TableGenerator定義一個主鍵值生成器 @TableGenerator(name="Emp_Gen") @Id@GeneratedValue(generator="Emp_Gen") private int id; __________________________________________ @TableGenerator(name="Emp_Gen", table="ID_GEN", pkColumnName="GEN_NAME", valueColumnName="GEN_VAL") @TableGenerator(name="Emp_Gen", table="ID_GEN", pkColumnName="GEN_NAME", valueColumnName="GEN_VAL", pkColumnValue="Add_Gen", initialValue=10000) @Id@GenerateValue(genarator="Add_Gen") SequenceGenerator定義一個主鍵值生成器 @GeneratedValue(stategy=Generation.SEQUENCE) private int id; @SequenceGenerator(name="Emp_Gen",sequenceName="Emp_Seq") @Id@SequencedValue(generator="Emp_Gen") private int id; _____________________________________________________________ @GeneratedValue(stategy=Generation.IDENTITY) ______________________________________________________________________________ @Column @Coulmn(name="e_id",insertable=false,updateable=false) private int eId; Column定義了映射到資料庫的欄位和屬性 · insertable: 是否允許插入 · updatable: 是否允許更新 @Temporal @Temporal(TemporalType.DATE | TIME | DATESTAMP) DATE:日期 TIME:時間 DATESTAMP:日期+時間 @Lob @Lob private byte[] picture; (圖片檔) ?? public enum EmployeeType{ FULL_TIME_EMPLOYEE, PART_TIME_EMPLOYEE, CONTRACT_EMPLOYEE} @Enumerated @Enumerated(EnumType.STRING | ORDINAL) private EmployeeType emptype; JPA2.0 ? @Access @Access(AccessType.FIELD | PROPERTY) http://download.oracle.com/javaee/6/api/javax/persistence/Basic.html @Transient ----->non-persistent 指定實体的非持久field或property ----------------------------------------------- 關聯式--四種 @OneToOne Employee(1)---------------------------ParkingSpace(1) @OneToOne @OneToOne(mappedBy="parking") private ParkingSpace parking private Employee employee cascade = CascadeType.ALL ? http://www.lixiao.name/archives/learn-openjpa_chapter-5-metadata.html ------------------------------------------------------------------------------------------- @OneToMany @ManyToOne Employee(n)---------------------------Department(1) @ManyToOne @OneToMany (mappedBy="depart) @JoinColumn(name = "DEPT_ID") <foreign key> private Department depart private Collection<Employee> employee @ManyToMany Employee(n)------------------------------Project(n) @ManyToMany @ManyToMany(mappedBy="pro") @JoinTable(name = "EMP_PROJ", joinColumns = @JoinColumn(name = "EMP_ID"), inverseJoinColumns = @JoinColumn(name = "PROJ_ID")) private Collection<Project>pro private Collection<Employee>employee ____________________________________________ @JoinColumn @JoinTable ___________________________________________________________________________________ @Embeddable @Embedded @Entity @Table(name="employee") employee @id id private int id; name private String name; salary private long salary; ----------------------------------------------------- @Embeddable public class Address { private String street; private String city; private String state; private String zip; } @Entity employee @Table(name="employee") id @id name private int id; salary private String name; street private long salary; city @Embedded state >PROVINEE private Address address zip >POSTAL_CO _________________________________________________________________________________ @AttributeOverrides @AttributeOverride @AttributeOverrides({@AttributeOverride(name=state,column=@Column(name="PROVINEE")), @AttributeOverride(name=zip,column=@Column(name="POSTAL_CO")) }) ------------------------------------------------------------------------------------------------------------- JPA2.0增加了兩個支持新的集合映射的註解：@ElementCollection 和 @CollectionTable。使用@ElementCollection註解指定集合的嵌入式物件 這些集合是獨立存儲在集合表中的 使用@CollectionTable註解指定集合表的詳細信息，如它包含的欄位。 @ElementCollection @ CollectionTable ------------------------------- @Embeddable public class FeatureType{ private int daysTaken; } @Entity public class Vehicle{ @Id int id; @ElementCollection @CollectionTable(name="VEH_OPTNS") Collection<FeatureType>optionalFeatures; 第一對註解@ElementCollection 和@CollectionTable指定FeatureType值存儲在VEH_OPTNS集合表中Vehicle VEH_OPTNS id Vehicle_id daysTaken _________________________________________________________________________ @Order By(ASC--[小-->大]/DESC[大-->小])--不包含支持維護一個持久性 JPA2.0 @OrderColumn--持久化提供者需要使用分離的欄位來維護，預設值是按物件的主鍵升序排序 ------------------------------------------ JPA2.0 @MayKeyColumn @MayKeyEnumerated @MayKey |
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