DATAJDBC-218 - The Column annotation affects the back reference too.

Also:
Added documentation for the new behavior.
Made the value of the column annotation optional by providing a default.

Original pull request: #83.

src/main/asciidoc/jdbc.adoc

@@ -131,7 +131,8 @@ You can change this name by implementing `NamingStrategy.getReverseColumnName(Re
 
 * `Map<simple type, some entity>` is considered a qualified one-to-many relationship.
 The table of the referenced entity is expected to have two additional columns: One named the same as the table of the referencing entity for the foreign key and one with the same name and an additional `_key` suffix for the map key.
-You can change this name by implementing `NamingStrategy.getReverseColumnName(RelationalPersistentProperty property)` and `NamingStrategy.getKeyColumn(RelationalPersistentProperty property)`, respectively.
+You can change this behavior by implementing `NamingStrategy.getReverseColumnName(RelationalPersistentProperty property)` and `NamingStrategy.getKeyColumn(RelationalPersistentProperty property)`, respectively.
+Alternatively you may annotate the attribute with `@Column(value="your_column_name", keyColumn="your_key_column_name")`
 
 * `List<some entity>` is mapped as a  `Map<Integer, some entity>`.
 

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

@@ -73,7 +73,13 @@ class BasicRelationalPersistentProperty extends AnnotationBasedPersistentPropert
 		Assert.notNull(context, "context must not be null.");
 
 		this.context = context;
-		this.columnName = Lazy.of(() -> Optional.ofNullable(findAnnotation(Column.class)).map(Column::value));
+
+		this.columnName = Lazy.of(() -> Optional.ofNullable( //
+				findAnnotation(Column.class)) //
+				.map(Column::value) //
+				.filter(StringUtils::hasText) //
+		);
+
 		this.keyColumnName = Lazy.of(() -> Optional.ofNullable( //
 				findAnnotation(Column.class)) //
 				.map(Column::keyColumn) //
@@ -120,7 +126,7 @@ class BasicRelationalPersistentProperty extends AnnotationBasedPersistentPropert
 
 	@Override
 	public String getReverseColumnName() {
-		return context.getNamingStrategy().getReverseColumnName(this);
+		return columnName.get().orElseGet(() -> context.getNamingStrategy().getReverseColumnName(this));
 	}
 
 	@Override

src/main/java/org/springframework/data/relational/core/mapping/Column.java

@@ -35,7 +35,7 @@ public @interface Column {
 	/**
 	 * The mapping column name.
 	 */
-	String value();
+	String value() default "";
 
 	/**
 	 * The column name for key columns of List or Map collections.

src/test/java/org/springframework/data/relational/core/mapping/BasicRelationalPersistentPropertyUnitTests.java

@@ -93,7 +93,7 @@ public class BasicRelationalPersistentPropertyUnitTests {
 				.getRequiredPersistentEntity(DummyEntity.class) //
 				.getRequiredPersistentProperty("someList");
 
-		assertThat(listProperty.getColumnName()).isEqualTo("dummy_column_name");
+		assertThat(listProperty.getReverseColumnName()).isEqualTo("dummy_column_name");
 		assertThat(listProperty.getKeyColumn()).isEqualTo("dummy_key_column_name");
 	}