Introduce @InsertOnlyProperty.

For Spring Data JDBC you may now annotate properties of the aggregate root with `@InsertOnlyProperty`.
Properties annotated in such way will be written to the database only during insert operations, but they will not be updated afterwards.

Closes #637

Author: schauder

spring-data-jdbc/src/main/java/org/springframework/data/jdbc/core/convert/SqlGenerator.java

@@ -1024,6 +1024,7 @@ static class Columns {
 		private final List<SqlIdentifier> idColumnNames = new ArrayList<>();
 		private final List<SqlIdentifier> nonIdColumnNames = new ArrayList<>();
 		private final Set<SqlIdentifier> readOnlyColumnNames = new HashSet<>();
+		private final Set<SqlIdentifier> insertOnlyColumnNames = new HashSet<>();
 		private final Set<SqlIdentifier> insertableColumns;
 		private final Set<SqlIdentifier> updatableColumns;
 
@@ -1045,6 +1046,7 @@ static class Columns {
 
 			updatable.removeAll(idColumnNames);
 			updatable.removeAll(readOnlyColumnNames);
+			updatable.removeAll(insertOnlyColumnNames);
 
 			this.updatableColumns = Collections.unmodifiableSet(updatable);
 		}
@@ -1077,6 +1079,10 @@ private void initSimpleColumnName(RelationalPersistentProperty property, String
 			if (!property.isWritable()) {
 				readOnlyColumnNames.add(columnName);
 			}
+
+			if (property.isInsertOnly()) {
+				insertOnlyColumnNames.add(columnName);
+			}
 		}
 
 		private void initEmbeddedColumnNames(RelationalPersistentProperty property, String prefix) {

spring-data-jdbc/src/main/java/org/springframework/data/jdbc/core/convert/SqlParametersFactory.java

@@ -95,7 +95,7 @@ <T> SqlIdentifierParameterSource forInsert(T instance, Class<T> domainType, Iden
 	 */
 	<T> SqlIdentifierParameterSource forUpdate(T instance, Class<T> domainType) {
 
-		return getParameterSource(instance, getRequiredPersistentEntity(domainType), "", Predicates.includeAll(),
+		return getParameterSource(instance, getRequiredPersistentEntity(domainType), "", RelationalPersistentProperty::isInsertOnly,
 				dialect.getIdentifierProcessing());
 	}
 

spring-data-jdbc/src/test/java/org/springframework/data/jdbc/core/JdbcAggregateTemplateIntegrationTests.java

@@ -64,6 +64,7 @@
 import org.springframework.data.jdbc.testing.TestDatabaseFeatures;
 import org.springframework.data.relational.core.conversion.DbActionExecutionException;
 import org.springframework.data.relational.core.mapping.Column;
+import org.springframework.data.relational.core.mapping.InsertOnlyProperty;
 import org.springframework.data.relational.core.mapping.MappedCollection;
 import org.springframework.data.relational.core.mapping.RelationalMappingContext;
 import org.springframework.data.relational.core.mapping.Table;
@@ -1031,6 +1032,20 @@ void updateIdOnlyAggregate() {
 		template.save(entity);
 	}
 
+	@Test // GH-637
+	void insertOnlyPropertyDoesNotGetUpdated() {
+
+		WithInsertOnly entity = new WithInsertOnly();
+		entity.insertOnly = "first value";
+
+		assertThat(template.save(entity).id).isNotNull();
+
+		entity.insertOnly = "second value";
+		template.save(entity);
+
+		assertThat(template.findById(entity.id, WithInsertOnly.class).insertOnly).isEqualTo("first value");
+	}
+
 	private <T extends Number> void saveAndUpdateAggregateWithVersion(VersionedAggregate aggregate,
 			Function<Number, T> toConcreteNumber) {
 		saveAndUpdateAggregateWithVersion(aggregate, toConcreteNumber, 0);
@@ -1462,10 +1477,16 @@ static class WithLocalDateTime {
 	}
 
 	@Table
-	class WithIdOnly {
+	static class WithIdOnly {
 		@Id Long id;
 	}
 
+	@Table
+	static class WithInsertOnly {
+		@Id Long id;
+		@InsertOnlyProperty
+		String insertOnly;
+	}
 
 	@Configuration
 	@Import(TestConfiguration.class)

spring-data-jdbc/src/test/resources/org.springframework.data.jdbc.core/JdbcAggregateTemplateIntegrationTests-hsql.sql

@@ -325,6 +325,12 @@ CREATE TABLE WITH_LOCAL_DATE_TIME
     TEST_TIME TIMESTAMP(9)
 );
 
+CREATE TABLE WITH_INSERT_ONLY
+(
+    ID BIGINT GENERATED BY DEFAULT AS IDENTITY (START WITH 1) PRIMARY KEY,
+    INSERT_ONLY VARCHAR(100)
+);
+
 CREATE TABLE WITH_ID_ONLY
 (
     ID BIGINT GENERATED BY DEFAULT AS IDENTITY (START WITH 1) PRIMARY KEY

spring-data-relational/src/main/java/org/springframework/data/relational/core/mapping/BasicRelationalPersistentProperty.java

@@ -199,6 +199,11 @@ public boolean shouldCreateEmptyEmbedded() {
 		return findAnnotation != null && OnEmpty.USE_EMPTY.equals(findAnnotation.onEmpty());
 	}
 
+	@Override
+	public boolean isInsertOnly() {
+		return findAnnotation(InsertOnlyProperty.class) != null;
+	}
+
 	private boolean isListLike() {
 		return isCollectionLike() && !Set.class.isAssignableFrom(this.getType());
 	}

spring-data-relational/src/main/java/org/springframework/data/relational/core/mapping/InsertOnlyProperty.java

@@ -0,0 +1,29 @@
+/*
+ * Copyright 2022 the original author or authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      https://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.springframework.data.relational.core.mapping;
+
+import java.lang.annotation.Documented;
+import java.lang.annotation.ElementType;
+import java.lang.annotation.Inherited;
+import java.lang.annotation.Retention;
+import java.lang.annotation.RetentionPolicy;
+import java.lang.annotation.Target;
+
+@Retention(RetentionPolicy.RUNTIME)
+@Target({ ElementType.FIELD, ElementType.METHOD, ElementType.ANNOTATION_TYPE })
+@Documented
+public @interface InsertOnlyProperty {
+}

spring-data-relational/src/main/java/org/springframework/data/relational/core/mapping/RelationalPersistentProperty.java

@@ -73,8 +73,13 @@ default String getEmbeddedPrefix() {
 
 	/**
 	 * Returns whether an empty embedded object is supposed to be created for this property.
-	 *
-	 * @return
 	 */
 	boolean shouldCreateEmptyEmbedded();
+
+	/**
+	 * Returns whether this property is only to be used during inserts and read.
+	 * 
+	 * @since 3.0
+	 */
+	boolean isInsertOnly();
 }

src/main/asciidoc/jdbc.adoc

@@ -435,6 +435,14 @@ Therefore, you have to reload it explicitly if you want to see data that was gen
 If the annotated attribute is an entity or collection of entities, it is represented by one or more separate rows in separate tables.
 Spring Data JDBC will not perform any insert, delete or update for these rows.
 
+[[jdbc.entity-persistence.insert-only-properties]]
+=== Insert Only Properties
+
+Attributes annotated with `@InsertOnlyProperty` will only be written to the database by Spring Data JDBC during insert operations.
+For updates these properties will be ignored.
+
+`@InsertOnlyProperty` is only supported for the aggregate root.
+
 [[jdbc.entity-persistence.optimistic-locking]]
 === Optimistic Locking