java:hibernate:valuegenerationtype

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--- java:hibernate:valuegenerationtype [2021/10/07 21:57]
kwon37xi
+++ java:hibernate:valuegenerationtype [2021/10/07 22:04] (현재)
kwon37xi [Example]
@@ 줄 5: / 줄 5: @@
   * 이를 기반으로 하여 [[https://docs.jboss.org/hibernate/orm/6.0/javadocs/org/hibernate/tuple/CreationTimestampGeneration.html|CreationTimestampGeneration]] [[https://docs.jboss.org/hibernate/orm/6.0/javadocs/org/hibernate/tuple/UpdateTimestampGeneration.html|UpdateTimestampGeneration]] 등이 만들어졌다.
   * see [[java:hibernate:generated|Hibernate @Generated]]
+===== Example =====
+<code java>
+@Entity(name = "Event")
+public static class Event {
+	@Id
+	@GeneratedValue
+	private Long id;
+	@Column(name = "`timestamp`")
+	@FunctionCreationTimestamp
+	private Date timestamp;
+	//Constructors, getters, and setters are omitted for brevity
+}
+@ValueGenerationType(generatedBy = FunctionCreationValueGeneration.class)
+@Retention(RetentionPolicy.RUNTIME)
+public @interface FunctionCreationTimestamp {}
+// DB를 통해 자동생성 지원
+public static class FunctionCreationValueGeneration
+		implements AnnotationValueGeneration<FunctionCreationTimestamp> {
+	@Override
+	public void initialize(FunctionCreationTimestamp annotation, Class<?> propertyType) {
+	}
+	/**
+	 * Generate value on INSERT
+	 * @return when to generate the value
+	 */
+	public GenerationTiming getGenerationTiming() {
+		return GenerationTiming.INSERT;
+	}
+	/**
+	 * Returns null because the value is generated by the database.
+	 * @return null
+	 */
+	public ValueGenerator<?> getValueGenerator() {
+		return null;
+	}
+	/**
+	 * Returns true because the value is generated by the database.
+	 * @return true
+	 */
+	public boolean referenceColumnInSql() {
+		return true;
+	}
+	/**
+	 * Returns the database-generated value
+	 * @return database-generated value
+	 */
+	public String getDatabaseGeneratedReferencedColumnValue() {
+		return "current_timestamp";
+	}
+}
+</code>
+쿼리가 아래처럼 실행된다.
+<code sql>
+INSERT INTO Event ("timestamp", id)
+VALUES (current_timestamp, 1)
+</code>
+<code java>
+// In memory 상에서 자동생성
+public static class FunctionCreationValueGeneration
+		implements AnnotationValueGeneration<FunctionCreationTimestamp> {
+	@Override
+	public void initialize(FunctionCreationTimestamp annotation, Class<?> propertyType) {
+	}
+	/**
+	 * Generate value on INSERT
+	 * @return when to generate the value
+	 */
+	public GenerationTiming getGenerationTiming() {
+		return GenerationTiming.INSERT;
+	}
+	/**
+	 * Returns the in-memory generated value
+	 * @return {@code true}
+	 */
+	public ValueGenerator<?> getValueGenerator() {
+		return (session, owner) -> new Date( );
+	}
+	/**
+	 * Returns false because the value is generated by the database.
+	 * @return false
+	 */
+	public boolean referenceColumnInSql() {
+		return false;
+	}
+	/**
+	 * Returns null because the value is generated in-memory.
+	 * @return null
+	 */
+	public String getDatabaseGeneratedReferencedColumnValue() {
+		return null;
+	}
+}
+</code>
+쿼리가 다음과 같이 날라간다.
+<code sql>
+INSERT INTO Event ("timestamp", id)
+VALUES ('Tue Mar 01 10:58:18 EET 2016', 1)
+</code>

java/hibernate/valuegenerationtype.1633611465.txt.gz · 마지막으로 수정됨: 2021/10/07 21:57 저자 kwon37xi