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

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

@@ -50,6 +50,7 @@ import java.util.stream.Collectors;
  * @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 @@ import org.springframework.transaction.annotation.Transactional;
  * @author Tyler Van Gorder
  * @author Clemens Hahn
  * @author Milan Milanov
+ * @author Mikhail Polivakha
  */
 @ContextConfiguration
 @Transactional
@@ -887,6 +888,12 @@ public class JdbcAggregateTemplateIntegrationTests {
 		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 @@ public class JdbcAggregateTemplateIntegrationTests {
 		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.jdbc.core.mapping.PersistentPropertyPathTestUtil
 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 @@ import org.springframework.data.relational.core.sql.Table;
  * @author Tom Hombergs
  * @author Milan Milanov
  * @author Myeonghyeon Lee
+ * @author Mikhail Polivakha
  */
 class SqlGeneratorUnitTests {
 
@@ -391,13 +394,22 @@ class SqlGeneratorUnitTests {
 	}
 
 	@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(insert).endsWith("()");
+		assertThat(insertSqlStatement).endsWith(" VALUES (DEFAULT) ");
+	}
+
+	@Test //DATAJDBC-557
+	void gerInsertForEmptyColumnListMsSqlServer() {
+		SqlGenerator sqlGenerator = createSqlGenerator(IdOnlyEntity.class, SqlServerDialect.INSTANCE);
+
+		String insertSqlStatement = sqlGenerator.getInsert(emptySet());
+
+		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
 );

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

@@ -12,6 +12,7 @@ DROP TABLE CHAIN2;
 DROP TABLE CHAIN1;
 DROP TABLE CHAIN0;
 DROP TABLE WITH_READ_ONLY;
+DROP TABLE WITH_ID_ONLY;
 
 CREATE TABLE LEGO_SET
 (
@@ -335,4 +336,9 @@ 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-relational/src/main/java/org/springframework/data/relational/core/dialect/Dialect.java

@@ -32,6 +32,7 @@ import org.springframework.data.relational.core.sql.render.SelectRenderContext;
  * @author Jens Schauder
  * @author Myeonghyeon Lee
  * @author Christoph Strobl
+ * @author Mikhail Polivakha
  * @since 1.1
  */
 public interface Dialect {
@@ -109,4 +110,13 @@ public interface Dialect {
 	default Set<Class<?>> simpleTypes() {
 		return Collections.emptySet();
 	}
+
+	/**
+	 * @return an appropriate {@link InsertWithDefaultValues } for that specific dialect.
+	 *         for most of the Dialects the default implementation will be valid, but, for
+	 *         example, in case of {@link SqlServerDialect} it is not
+	 */
+	default InsertWithDefaultValues getSqlInsertWithDefaultValues() {
+		return new InsertWithDefaultValues() {};
+	}
 }

spring-data-relational/src/main/java/org/springframework/data/relational/core/dialect/InsertWithDefaultValues.java

@@ -0,0 +1,17 @@
+package org.springframework.data.relational.core.dialect;
+
+import org.springframework.data.relational.core.mapping.InsertDefaultValues;
+
+/**
+ * This interface aggregates information about an Insert with default values statement.
+ * @author Mikhail Polivakha
+ */
+public interface InsertWithDefaultValues {
+
+    /**
+     * @return the part of the sql statement, that follows after <b>INSERT INTO table</b>
+     */
+    default String getDefaultInsertPart() {
+        return InsertDefaultValues.DEFAULT.getDefaultInsertPart();
+    }
+}

spring-data-relational/src/main/java/org/springframework/data/relational/core/dialect/RenderContextFactory.java

@@ -16,6 +16,7 @@
 package org.springframework.data.relational.core.dialect;
 
 import org.springframework.data.relational.core.sql.IdentifierProcessing;
+import org.springframework.data.relational.core.sql.render.InsertRenderContext;
 import org.springframework.data.relational.core.sql.render.NamingStrategies;
 import org.springframework.data.relational.core.sql.render.RenderContext;
 import org.springframework.data.relational.core.sql.render.RenderNamingStrategy;
@@ -26,6 +27,7 @@ import org.springframework.util.Assert;
  * Factory for {@link RenderContext} based on {@link Dialect}.
  *
  * @author Mark Paluch
+ * @author Mikhail Polivakha
  * @since 1.1
  */
 public class RenderContextFactory {
@@ -65,9 +67,9 @@ public class RenderContextFactory {
 	 */
 	public RenderContext createRenderContext() {
 
-		SelectRenderContext select = dialect.getSelectContext();
+		SelectRenderContext selectRenderContext = dialect.getSelectContext();
 
-		return new DialectRenderContext(namingStrategy, dialect.getIdentifierProcessing(), select);
+		return new DialectRenderContext(namingStrategy, dialect, selectRenderContext);
 	}
 
 	/**
@@ -76,17 +78,18 @@ public class RenderContextFactory {
 	static class DialectRenderContext implements RenderContext {
 
 		private final RenderNamingStrategy renderNamingStrategy;
-		private final IdentifierProcessing identifierProcessing;
 		private final SelectRenderContext selectRenderContext;
+		private final Dialect renderingDialect;
 
-		DialectRenderContext(RenderNamingStrategy renderNamingStrategy, IdentifierProcessing identifierProcessing, SelectRenderContext selectRenderContext) {
+		DialectRenderContext(RenderNamingStrategy renderNamingStrategy, Dialect renderingDialect, SelectRenderContext selectRenderContext) {
 
 			Assert.notNull(renderNamingStrategy, "RenderNamingStrategy must not be null");
-			Assert.notNull(identifierProcessing, "IdentifierProcessing must not be null");
+			Assert.notNull(renderingDialect, "renderingDialect must not be null");
+			Assert.notNull(renderingDialect.getIdentifierProcessing(), "IdentifierProcessing of renderingDialect must not be null");
 			Assert.notNull(selectRenderContext, "SelectRenderContext must not be null");
 
 			this.renderNamingStrategy = renderNamingStrategy;
-			this.identifierProcessing = identifierProcessing;
+			this.renderingDialect = renderingDialect;
 			this.selectRenderContext = selectRenderContext;
 		}
 
@@ -105,7 +108,7 @@ public class RenderContextFactory {
 		 */
 		@Override
 		public IdentifierProcessing getIdentifierProcessing() {
-			return identifierProcessing;
+			return renderingDialect.getIdentifierProcessing();
 		}
 
 		/*
@@ -113,8 +116,18 @@ public class RenderContextFactory {
 		 * @see org.springframework.data.relational.core.sql.render.RenderContext#getSelect()
 		 */
 		@Override
-		public SelectRenderContext getSelect() {
+		public SelectRenderContext getSelectRenderContext() {
 			return selectRenderContext;
 		}
+
+		@Override
+		public InsertRenderContext getInsertRenderContext() {
+			return new InsertRenderContext() {
+				@Override
+				public String getInsertDefaultValuesPartSQL() {
+					return renderingDialect.getSqlInsertWithDefaultValues().getDefaultInsertPart();
+				}
+			};
+		}
 	}
-}
+}

spring-data-relational/src/main/java/org/springframework/data/relational/core/dialect/SqlServerDialect.java

@@ -15,6 +15,7 @@
  */
 package org.springframework.data.relational.core.dialect;
 
+import org.springframework.data.relational.core.mapping.InsertDefaultValues;
 import org.springframework.data.relational.core.sql.IdentifierProcessing;
 import org.springframework.data.relational.core.sql.LockOptions;
 import org.springframework.data.relational.core.sql.render.SelectRenderContext;
@@ -26,6 +27,7 @@ import org.springframework.data.util.Lazy;
  * @author Mark Paluch
  * @author Myeonghyeon Lee
  * @author Jens Schauder
+ * @author Mikhail Polivakha
  * @since 1.1
  */
 public class SqlServerDialect extends AbstractDialect {
@@ -150,4 +152,14 @@ public class SqlServerDialect extends AbstractDialect {
 	public IdentifierProcessing getIdentifierProcessing() {
 		return IdentifierProcessing.NONE;
 	}
+
+	@Override
+	public InsertWithDefaultValues getSqlInsertWithDefaultValues() {
+		return new InsertWithDefaultValues() {
+			@Override
+			public String getDefaultInsertPart() {
+				return InsertDefaultValues.MS_SQL_SERVER.getDefaultInsertPart();
+			}
+		};
+	}
 }

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

@@ -0,0 +1,28 @@
+package org.springframework.data.relational.core.mapping;
+
+import org.springframework.data.relational.core.dialect.Dialect;
+import org.springframework.data.relational.core.dialect.InsertWithDefaultValues;
+
+/**
+ * In the scope of Insert with default values SQL statement, for example
+ * <b>INSERT INTO SCHEMA.TABLE VALUES (DEFAULT)</b>
+ * this enum represents the default values part in different {@link Dialect}s
+ *
+ * @author Mikhail Polivakha
+ * @see InsertWithDefaultValues
+ */
+public enum InsertDefaultValues {
+
+    DEFAULT(" VALUES (DEFAULT) "),
+    MS_SQL_SERVER(" DEFAULT VALUES ");
+
+    private final String defaultInsertPart;
+
+    InsertDefaultValues(String defaultInsertPart) {
+        this.defaultInsertPart = defaultInsertPart;
+    }
+
+    public String getDefaultInsertPart() {
+        return defaultInsertPart;
+    }
+}

spring-data-relational/src/main/java/org/springframework/data/relational/core/sql/render/InsertRenderContext.java

@@ -0,0 +1,18 @@
+package org.springframework.data.relational.core.sql.render;
+
+import org.springframework.data.relational.core.mapping.InsertDefaultValues;
+import org.springframework.data.relational.core.sql.Insert;
+
+/**
+ * This interface encapsulates the details about how to
+ * process {@link Insert} SQL statement
+ *
+ * @see RenderContext
+ * @author Mikhail Polivakha
+ */
+public interface InsertRenderContext {
+
+    default String getInsertDefaultValuesPartSQL() {
+        return InsertDefaultValues.DEFAULT.getDefaultInsertPart();
+    }
+}

spring-data-relational/src/main/java/org/springframework/data/relational/core/sql/render/InsertStatementVisitor.java

@@ -15,51 +15,42 @@
  */
 package org.springframework.data.relational.core.sql.render;
 
+import org.jetbrains.annotations.NotNull;
 import org.springframework.data.relational.core.sql.Column;
 import org.springframework.data.relational.core.sql.Insert;
 import org.springframework.data.relational.core.sql.Into;
 import org.springframework.data.relational.core.sql.Values;
 import org.springframework.data.relational.core.sql.Visitable;
+import org.springframework.util.Assert;
 
 /**
  * {@link PartRenderer} for {@link Insert} statements.
  *
  * @author Mark Paluch
  * @author Jens Schauder
+ * @author Mikhail Polivakha
  * @since 1.1
  */
 class InsertStatementVisitor extends DelegatingVisitor implements PartRenderer {
 
-	private StringBuilder builder = new StringBuilder();
-	private StringBuilder into = new StringBuilder();
-	private StringBuilder columns = new StringBuilder();
-	private StringBuilder values = new StringBuilder();
+	private final StringBuilder builder = new StringBuilder();
+	private final StringBuilder into = new StringBuilder();
+	private final StringBuilder columns = new StringBuilder();
+	private final StringBuilder values = new StringBuilder();
 
-	private IntoClauseVisitor intoClauseVisitor;
-	private ColumnVisitor columnVisitor;
-	private ValuesVisitor valuesVisitor;
+	private final IntoClauseVisitor intoClauseVisitor;
+	private final ColumnVisitor columnVisitor;
+	private final ValuesVisitor valuesVisitor;
+	private final RenderContext renderContext;
 
-	InsertStatementVisitor(RenderContext context) {
+	InsertStatementVisitor(RenderContext renderContext) {
 
-		this.intoClauseVisitor = new IntoClauseVisitor(context, it -> {
+		Assert.notNull(renderContext, "renderContext must not be null!");
 
-			if (into.length() != 0) {
-				into.append(", ");
-			}
-
-			into.append(it);
-		});
-
-		this.columnVisitor = new ColumnVisitor(context, false, it -> {
-
-			if (columns.length() != 0) {
-				columns.append(", ");
-			}
-
-			columns.append(it);
-		});
-
-		this.valuesVisitor = new ValuesVisitor(context, values::append);
+		this.renderContext = renderContext;
+		this.intoClauseVisitor = createIntoClauseVisitor(renderContext);
+		this.columnVisitor = createColumnVisitor(renderContext);
+		this.valuesVisitor = new ValuesVisitor(renderContext, values::append);
 	}
 
 	/*
@@ -97,11 +88,9 @@ class InsertStatementVisitor extends DelegatingVisitor implements PartRenderer {
 
 			builder.append(" INTO ").append(into);
 
-			if (columns.length() != 0) {
-				builder.append(" (").append(columns).append(")");
-			}
+			addInsertColumnsIfPresent();
 
-			builder.append(" VALUES (").append(values).append(")");
+			addInsertValuesIfPresentElseDefault();
 
 			return Delegation.leave();
 		}
@@ -109,6 +98,24 @@ class InsertStatementVisitor extends DelegatingVisitor implements PartRenderer {
 		return Delegation.retain();
 	}
 
+	private void addInsertValuesIfPresentElseDefault() {
+		if (values.length() != 0) {
+			builder.append(" VALUES (").append(values).append(")");
+		} else {
+			addInsertWithDefaultValuesToBuilder();
+		}
+	}
+
+	private void addInsertColumnsIfPresent() {
+		if (columns.length() != 0) {
+			builder.append(" (").append(columns).append(")");
+		}
+	}
+
+	private void addInsertWithDefaultValuesToBuilder() {
+		builder.append(renderContext.getInsertRenderContext().getInsertDefaultValuesPartSQL());
+	}
+
 	/*
 	 * (non-Javadoc)
 	 * @see org.springframework.data.relational.core.sql.render.PartRenderer#getRenderedPart()
@@ -117,4 +124,28 @@ class InsertStatementVisitor extends DelegatingVisitor implements PartRenderer {
 	public CharSequence getRenderedPart() {
 		return builder;
 	}
+
+	@NotNull
+	private ColumnVisitor createColumnVisitor(RenderContext context) {
+		return new ColumnVisitor(context, false, it -> {
+
+			if (columns.length() != 0) {
+				columns.append(", ");
+			}
+
+			columns.append(it);
+		});
+	}
+
+	@NotNull
+	private IntoClauseVisitor createIntoClauseVisitor(RenderContext context) {
+		return new IntoClauseVisitor(context, it -> {
+
+			if (into.length() != 0) {
+				into.append(", ");
+			}
+
+			into.append(it);
+		});
+	}
 }

spring-data-relational/src/main/java/org/springframework/data/relational/core/sql/render/RenderContext.java

@@ -21,6 +21,7 @@ import org.springframework.data.relational.core.sql.IdentifierProcessing;
  * Render context providing {@link RenderNamingStrategy} and other resources that are required during rendering.
  *
  * @author Mark Paluch
+ * @author Mikhail Polivakha
  * @since 1.1
  */
 public interface RenderContext {
@@ -43,5 +44,10 @@ public interface RenderContext {
 	/**
 	 * @return the {@link SelectRenderContext}.
 	 */
-	SelectRenderContext getSelect();
+	SelectRenderContext getSelectRenderContext();
+
+	/**
+	 * @return the {@link InsertRenderContext}
+	 */
+	InsertRenderContext getInsertRenderContext();
 }

spring-data-relational/src/main/java/org/springframework/data/relational/core/sql/render/SelectStatementVisitor.java

@@ -50,7 +50,7 @@ class SelectStatementVisitor extends DelegatingVisitor implements PartRenderer {
 	SelectStatementVisitor(RenderContext context) {
 
 		this.context = context;
-		this.selectRenderContext = context.getSelect();
+		this.selectRenderContext = context.getSelectRenderContext();
 		this.selectListVisitor = new SelectListVisitor(context, selectList::append);
 		this.orderByClauseVisitor = new OrderByClauseVisitor(context);
 		this.fromClauseVisitor = new FromClauseVisitor(context, it -> {

spring-data-relational/src/main/java/org/springframework/data/relational/core/sql/render/SimpleRenderContext.java

@@ -37,10 +37,15 @@ final class SimpleRenderContext implements RenderContext {
 	}
 
 	@Override
-	public SelectRenderContext getSelect() {
+	public SelectRenderContext getSelectRenderContext() {
 		return DefaultSelectRenderContext.INSTANCE;
 	}
 
+	@Override
+	public InsertRenderContext getInsertRenderContext() {
+		return new InsertRenderContext() {};
+	}
+
 	public RenderNamingStrategy getNamingStrategy() {
 		return this.namingStrategy;
 	}

spring-data-relational/src/main/java/org/springframework/data/relational/core/sql/render/SqlRenderer.java

@@ -69,16 +69,6 @@ public class SqlRenderer implements Renderer {
 		return create().render(select);
 	}
 
-	/**
-	 * Renders a {@link Insert} statement into its SQL representation.
-	 *
-	 * @param insert must not be {@literal null}.
-	 * @return the rendered statement.
-	 */
-	public static String toString(Insert insert) {
-		return create().render(insert);
-	}
-
 	/**
 	 * Renders a {@link Update} statement into its SQL representation.
 	 *
@@ -120,10 +110,8 @@ public class SqlRenderer implements Renderer {
 	 */
 	@Override
 	public String render(Insert insert) {
-
 		InsertStatementVisitor visitor = new InsertStatementVisitor(context);
 		insert.visit(visitor);
-
 		return visitor.getRenderedPart().toString();
 	}
 

spring-data-relational/src/test/java/org/springframework/data/relational/core/sql/render/InsertRendererUnitTests.java

@@ -68,7 +68,7 @@ public class InsertRendererUnitTests {
 
 		Insert insert = Insert.builder().into(bar).build();
 
-		assertThat(SqlRenderer.toString(insert)).isEqualTo("INSERT INTO bar VALUES ()");
+		assertThat(SqlRenderer.toString(insert)).isEqualTo("INSERT INTO bar VALUES (DEFAULT)");
 	}
 
 }