DATAJDBC-557 - Fix save on entity only have id and collections.

Author: lseeker

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

@@ -115,7 +115,7 @@ public <T> Object insert(T instance, Class<T> domainType, Identifier identifier)
 		identifier.forEach((name, value, type) -> addConvertedPropertyValue(parameterSource, name, value, type));
 
 		Object idValue = getIdValueOrNull(instance, persistentEntity);
-		if (idValue != null) {
+		if (idValue != null || parameterSource.getIdentifiers().isEmpty()) {
 
 			RelationalPersistentProperty idProperty = persistentEntity.getRequiredIdProperty();
 			addConvertedPropertyValue(parameterSource, idProperty, idValue, idProperty.getColumnName());

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

@@ -610,6 +610,10 @@ private UpdateBuilder.UpdateWhereAndOr createBaseUpdate() {
 						getBindMarker(columnName))) //
 				.collect(Collectors.toList());
 
+		if (assignments.isEmpty()) {
+			assignments.add(Assignments.value(getIdColumn(), getBindMarker(entity.getIdColumn())));
+		}
+
 		return Update.builder() //
 				.table(table) //
 				.set(assignments) //