Add test. Polishing.

Original pull request #1629

Author: kobaeugenea

spring-data-jdbc/src/main/java/org/springframework/data/jdbc/core/mapping/schema/ForeignKey.java

@@ -1,7 +1,5 @@
 package org.springframework.data.jdbc.core.mapping.schema;
 
-import java.util.Objects;
-
 /**
  * Models a Foreign Key for generating SQL for Schema generation.
  *
@@ -10,18 +8,4 @@
  */
 record ForeignKey(String name, String tableName, String columnName, String referencedTableName,
 									String referencedColumnName) {
-	@Override
-	public boolean equals(Object o) {
-		if (this == o)
-			return true;
-		if (o == null || getClass() != o.getClass())
-			return false;
-		ForeignKey that = (ForeignKey) o;
-		return Objects.equals(name, that.name);
-	}
-
-	@Override
-	public int hashCode() {
-		return Objects.hash(name);
-	}
 }

spring-data-jdbc/src/main/java/org/springframework/data/jdbc/core/mapping/schema/SchemaDiff.java

@@ -96,7 +96,7 @@ private static List<TableDiff> diffTable(Tables mappedEntities, Map<String, Tabl
 			// Identify deleted columns
 			tableDiff.columnsToDrop().addAll(findDiffs(mappedColumns, existingColumns, nameComparator));
 			// Identify added columns and add columns in order. This order can interleave with existing columns.
-			List<Column> addedColumns = new ArrayList<>(findDiffs(existingColumns, mappedColumns, nameComparator));
+			Collection<Column> addedColumns = findDiffs(existingColumns, mappedColumns, nameComparator);
 			for (Column column : mappedEntity.columns()) {
 				if (addedColumns.contains(column)) {
 					tableDiff.columnsToAdd().add(column);
@@ -107,9 +107,9 @@ private static List<TableDiff> diffTable(Tables mappedEntities, Map<String, Tabl
 					nameComparator);
 			Map<String, ForeignKey> existingForeignKeys = createMapping(existingTable.foreignKeys(), ForeignKey::name,
 					nameComparator);
-			// Identify deleted columns
+			// Identify deleted foreign keys
 			tableDiff.fkToDrop().addAll(findDiffs(mappedForeignKeys, existingForeignKeys, nameComparator));
-			// Identify added columns
+			// Identify added foreign keys
 			tableDiff.fkToAdd().addAll(findDiffs(existingForeignKeys, mappedForeignKeys, nameComparator));
 
 			tableDiffs.add(tableDiff);

spring-data-jdbc/src/test/java/org/springframework/data/jdbc/core/mapping/schema/LiquibaseChangeSetWriterUnitTests.java

@@ -119,6 +119,39 @@ void fieldForFkShouldNotBeCreatedTwice() {
 		assertThat(columns).extracting(ColumnConfig::getName).containsExactly("id", "tables_id");
 	}
 
+	@Test // GH-1599
+	void createForeignKeyForNestedEntities() {
+
+		RelationalMappingContext context = new RelationalMappingContext();
+		context.getRequiredPersistentEntity(SetOfTables.class);
+
+		LiquibaseChangeSetWriter writer = new LiquibaseChangeSetWriter(context);
+
+		ChangeSet changeSet = writer.createChangeSet(ChangeSetMetadata.create(), new DatabaseChangeLog());
+
+		Optional<Change> tablesFkOptional = changeSet.getChanges().stream().filter(change -> {
+			return change instanceof AddForeignKeyConstraintChange
+					&& ((AddForeignKeyConstraintChange) change).getBaseTableName().equals("other_table");
+		}).findFirst();
+		assertThat(tablesFkOptional.isPresent()).isTrue();
+		AddForeignKeyConstraintChange tableFk = (AddForeignKeyConstraintChange) tablesFkOptional.get();
+		assertThat(tableFk.getBaseTableName()).isEqualTo("other_table");
+		assertThat(tableFk.getBaseColumnNames()).isEqualTo("tables");
+		assertThat(tableFk.getReferencedTableName()).isEqualTo("tables");
+		assertThat(tableFk.getReferencedColumnNames()).isEqualTo("id");
+
+		Optional<Change> setOfTablesFkOptional = changeSet.getChanges().stream().filter(change -> {
+			return change instanceof AddForeignKeyConstraintChange
+					&& ((AddForeignKeyConstraintChange) change).getBaseTableName().equals("tables");
+		}).findFirst();
+		assertThat(setOfTablesFkOptional.isPresent()).isTrue();
+		AddForeignKeyConstraintChange setOfTablesFk = (AddForeignKeyConstraintChange) setOfTablesFkOptional.get();
+		assertThat(setOfTablesFk.getBaseTableName()).isEqualTo("tables");
+		assertThat(setOfTablesFk.getBaseColumnNames()).isEqualTo("set_id");
+		assertThat(setOfTablesFk.getReferencedTableName()).isEqualTo("set_of_tables");
+		assertThat(setOfTablesFk.getReferencedColumnNames()).isEqualTo("id");
+	}
+
 	@org.springframework.data.relational.core.mapping.Table
 	static class VariousTypes {
 		@Id long id;
@@ -141,6 +174,13 @@ static class Tables {
 		Set<OtherTable> tables;
 	}
 
+	@org.springframework.data.relational.core.mapping.Table
+	static class SetOfTables {
+		@Id int id;
+		@MappedCollection(idColumn = "set_id")
+		Set<Tables> setOfTables;
+	}
+
 	@org.springframework.data.relational.core.mapping.Table
 	static class DifferentTables {
 		@Id int id;