Support inserts for id only entities.

This broke in the past for some databases that do not support empty value lists.

Closes #777
Original pull request #1047

Author: mipo256

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

@@ -50,6 +50,7 @@
  * @author Tyler Van Gorder
  * @author Milan Milanov
  * @author Myeonghyeon Lee
+ * @author Mikhail Polivakha
  */
 class SqlGenerator {
 
@@ -92,12 +93,14 @@ class SqlGenerator {
 	SqlGenerator(RelationalMappingContext mappingContext, JdbcConverter converter, RelationalPersistentEntity<?> entity,
 			Dialect dialect) {
 
+		final RenderContextFactory renderContextFactory = new RenderContextFactory(dialect);
+
 		this.mappingContext = mappingContext;
 		this.entity = entity;
 		this.sqlContext = new SqlContext(entity);
-		this.sqlRenderer = SqlRenderer.create(new RenderContextFactory(dialect).createRenderContext());
+		this.sqlRenderer = SqlRenderer.create(renderContextFactory.createRenderContext());
 		this.columns = new Columns(entity, mappingContext, converter);
-		this.renderContext = new RenderContextFactory(dialect).createRenderContext();
+		this.renderContext = renderContextFactory.createRenderContext();
 	}
 
 	/**

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

@@ -80,6 +80,7 @@
  * @author Tyler Van Gorder
  * @author Clemens Hahn
  * @author Milan Milanov
+ * @author Mikhail Polivakha
  */
 @ContextConfiguration
 @Transactional
@@ -887,6 +888,12 @@ public void saveAndLoadDateTimeWithMicrosecondPrecision() {
 		assertThat(loaded.testTime).isEqualTo(entity.testTime);
 	}
 
+	@Test // DATAJDBC-557
+	public void insertWithIdOnly() {
+		WithIdOnly entity = new WithIdOnly();
+		assertThat(template.save(entity).id).isNotNull();
+	}
+
 	private <T extends Number> void saveAndUpdateAggregateWithVersion(VersionedAggregate aggregate,
 			Function<Number, T> toConcreteNumber) {
 		saveAndUpdateAggregateWithVersion(aggregate, toConcreteNumber, 0);
@@ -1254,6 +1261,11 @@ static class WithLocalDateTime {
 		LocalDateTime testTime;
 	}
 
+	@Table
+	class WithIdOnly {
+		@Id Long id;
+	}
+
 	@Configuration
 	@Import(TestConfiguration.class)
 	static class Config {

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

@@ -39,6 +39,8 @@
 import org.springframework.data.mapping.PersistentPropertyPath;
 import org.springframework.data.relational.core.dialect.AnsiDialect;
 import org.springframework.data.relational.core.dialect.Dialect;
+import org.springframework.data.relational.core.dialect.PostgresDialect;
+import org.springframework.data.relational.core.dialect.SqlServerDialect;
 import org.springframework.data.relational.core.mapping.Column;
 import org.springframework.data.relational.core.mapping.NamingStrategy;
 import org.springframework.data.relational.core.mapping.PersistentPropertyPathExtension;
@@ -61,6 +63,7 @@
  * @author Tom Hombergs
  * @author Milan Milanov
  * @author Myeonghyeon Lee
+ * @author Mikhail Polivakha
  */
 class SqlGeneratorUnitTests {
 
@@ -391,13 +394,22 @@ void updateWithVersion() {
 	}
 
 	@Test // DATAJDBC-264
-	void getInsertForEmptyColumnList() {
+	void getInsertForEmptyColumnListPostgres() {
 
-		SqlGenerator sqlGenerator = createSqlGenerator(IdOnlyEntity.class);
+		SqlGenerator sqlGenerator = createSqlGenerator(IdOnlyEntity.class, PostgresDialect.INSTANCE);
 
-		String insert = sqlGenerator.getInsert(emptySet());
+		String insertSqlStatement = sqlGenerator.getInsert(emptySet());
+
+		assertThat(insertSqlStatement).endsWith(" VALUES (DEFAULT) ");
+	}
+
+	@Test //DATAJDBC-557
+	void gerInsertForEmptyColumnListMsSqlServer() {
+		SqlGenerator sqlGenerator = createSqlGenerator(IdOnlyEntity.class, SqlServerDialect.INSTANCE);
+
+		String insertSqlStatement = sqlGenerator.getInsert(emptySet());
 
-		assertThat(insert).endsWith("()");
+		assertThat(insertSqlStatement).endsWith(" DEFAULT VALUES ");
 	}
 
 	@Test // DATAJDBC-334

spring-data-jdbc/src/test/resources/org.springframework.data.jdbc.core/JdbcAggregateTemplateIntegrationTests-db2.sql

@@ -37,6 +37,8 @@ DROP TABLE WITH_READ_ONLY;
 DROP TABLE VERSIONED_AGGREGATE;
 DROP TABLE WITH_LOCAL_DATE_TIME;
 
+DROP TABLE WITH_ID_ONLY;
+
 CREATE TABLE LEGO_SET
 (
   "id1"  BIGINT GENERATED BY DEFAULT AS IDENTITY (START WITH 1) PRIMARY KEY,
@@ -350,4 +352,9 @@ CREATE TABLE WITH_LOCAL_DATE_TIME
 (
   ID BIGINT NOT NULL PRIMARY KEY,
   TEST_TIME TIMESTAMP(9)
+);
+
+CREATE TABLE WITH_ID_ONLY
+(
+  ID BIGINT GENERATED BY DEFAULT AS IDENTITY (START WITH 1) PRIMARY KEY
 );

spring-data-jdbc/src/test/resources/org.springframework.data.jdbc.core/JdbcAggregateTemplateIntegrationTests-h2.sql

@@ -321,4 +321,9 @@ CREATE TABLE WITH_LOCAL_DATE_TIME
 (
     ID        BIGINT PRIMARY KEY,
     TEST_TIME TIMESTAMP(9) WITHOUT TIME ZONE
+);
+
+CREATE TABLE WITH_ID_ONLY
+(
+    ID SERIAL PRIMARY KEY
 );

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

@@ -323,4 +323,9 @@ CREATE TABLE WITH_LOCAL_DATE_TIME
 (
     ID        BIGINT PRIMARY KEY,
     TEST_TIME TIMESTAMP(9)
-);
+);
+
+CREATE TABLE WITH_ID_ONLY
+(
+    ID BIGINT GENERATED BY DEFAULT AS IDENTITY (START WITH 1) PRIMARY KEY
+)

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

@@ -296,4 +296,9 @@ CREATE TABLE WITH_LOCAL_DATE_TIME
 (
   ID BIGINT PRIMARY KEY,
   TEST_TIME TIMESTAMP(6)
+);
+
+CREATE TABLE WITH_ID_ONLY
+(
+  ID BIGINT AUTO_INCREMENT PRIMARY KEY
 );

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

@@ -324,4 +324,11 @@ CREATE TABLE WITH_LOCAL_DATE_TIME
 (
   ID BIGINT PRIMARY KEY,
   TEST_TIME datetime2(7)
+);
+
+DROP TABLE IF EXISTS WITH_ID_ONLY;
+
+CREATE TABLE WITH_ID_ONLY
+(
+  ID BIGINT IDENTITY PRIMARY KEY
 );

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

@@ -301,4 +301,9 @@ CREATE TABLE WITH_LOCAL_DATE_TIME
 (
   ID BIGINT PRIMARY KEY,
   TEST_TIME TIMESTAMP(6)
+);
+
+CREATE TABLE WITH_ID_ONLY
+(
+  ID BIGINT AUTO_INCREMENT PRIMARY KEY
 );

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

@@ -28,6 +28,7 @@ DROP TABLE NO_ID_MAP_CHAIN4 CASCADE CONSTRAINTS PURGE;
 DROP TABLE VERSIONED_AGGREGATE CASCADE CONSTRAINTS PURGE;
 DROP TABLE WITH_READ_ONLY CASCADE CONSTRAINTS PURGE;
 DROP TABLE WITH_LOCAL_DATE_TIME CASCADE CONSTRAINTS PURGE;
+DROP TABLE WITH_ID_ONLY CASCADE CONSTRAINTS PURGE;
 
 CREATE TABLE LEGO_SET
 (
@@ -332,4 +333,9 @@ CREATE TABLE WITH_LOCAL_DATE_TIME
 (
   ID        NUMBER PRIMARY KEY,
   TEST_TIME TIMESTAMP(9)
+);
+
+CREATE TABLE WITH_ID_ONLY
+(
+  ID NUMBER GENERATED by default on null as IDENTITY PRIMARY KEY
 );