feat: add lookup column type

appinfo/routes.php

@@ -51,6 +51,9 @@
 		['name' => 'api1#updateColumn',	'url' => '/api/1/columns/{columnId}', 'verb' => 'PUT'],
 		['name' => 'api1#getColumn',	'url' => '/api/1/columns/{columnId}', 'verb' => 'GET'],
 		['name' => 'api1#deleteColumn',	'url' => '/api/1/columns/{columnId}', 'verb' => 'DELETE'],
+		// -> relations
+		['name' => 'api1#indexTableRelations', 'url' => '/api/1/tables/{tableId}/relations', 'verb' => 'GET'],
+		['name' => 'api1#indexViewRelations', 'url' => '/api/1/views/{viewId}/relations', 'verb' => 'GET'],
 		// -> rows
 		['name' => 'api1#indexTableRowsSimple',	'url' => '/api/1/tables/{tableId}/rows/simple', 'verb' => 'GET'],
 		['name' => 'api1#indexTableRows',	'url' => '/api/1/tables/{tableId}/rows', 'verb' => 'GET'],

lib/Controller/Api1Controller.php

@@ -23,6 +23,7 @@
 use OCA\Tables\ResponseDefinitions;
 use OCA\Tables\Service\ColumnService;
 use OCA\Tables\Service\ImportService;
+use OCA\Tables\Service\RelationService;
 use OCA\Tables\Service\RowService;
 use OCA\Tables\Service\ShareService;
 use OCA\Tables\Service\TableService;
@@ -57,6 +58,7 @@ class Api1Controller extends ApiController {
 	private RowService $rowService;
 	private ImportService $importService;
 	private ViewService $viewService;
+	private RelationService $relationService;
 	private ViewMapper $viewMapper;
 	private IL10N $l10N;
 
@@ -77,6 +79,7 @@ public function __construct(
 		RowService $rowService,
 		ImportService $importService,
 		ViewService $viewService,
+		RelationService $relationService,
 		ViewMapper $viewMapper,
 		V1Api $v1Api,
 		LoggerInterface $logger,
@@ -90,6 +93,7 @@ public function __construct(
 		$this->rowService = $rowService;
 		$this->importService = $importService;
 		$this->viewService = $viewService;
+		$this->relationService = $relationService;
 		$this->viewMapper = $viewMapper;
 		$this->userId = $userId;
 		$this->v1Api = $v1Api;
@@ -803,13 +807,77 @@ public function indexViewColumns(int $viewId): DataResponse {
 		}
 	}
 
+	/**
+	 * Get all relation data for a table
+	 *
+	 * @param int $tableId Table ID
+	 * @return DataResponse<Http::STATUS_OK, array<string, array<string, array{id: int, label: string}>>, array{}>|DataResponse<Http::STATUS_FORBIDDEN|Http::STATUS_INTERNAL_SERVER_ERROR|Http::STATUS_NOT_FOUND, array{message: string}, array{}>
+	 *
+	 * 200: Relation data returned
+	 * 403: No permissions
+	 * 404: Not found
+	 */
+	#[NoAdminRequired]
+	#[NoCSRFRequired]
+	#[CORS]
+	#[RequirePermission(permission: Application::PERMISSION_READ, type: Application::NODE_TYPE_TABLE, idParam: 'tableId')]
+	public function indexTableRelations(int $tableId): DataResponse {
+		try {
+			return new DataResponse($this->relationService->getRelationsForTable($tableId));
+		} catch (PermissionError $e) {
+			$this->logger->warning('A permission error occurred: ' . $e->getMessage(), ['exception' => $e]);
+			$message = ['message' => $e->getMessage()];
+			return new DataResponse($message, Http::STATUS_FORBIDDEN);
+		} catch (InternalError $e) {
+			$this->logger->error('An internal error or exception occurred: ' . $e->getMessage(), ['exception' => $e]);
+			$message = ['message' => $e->getMessage()];
+			return new DataResponse($message, Http::STATUS_INTERNAL_SERVER_ERROR);
+		} catch (NotFoundError $e) {
+			$this->logger->info('A not found error occurred: ' . $e->getMessage(), ['exception' => $e]);
+			$message = ['message' => $e->getMessage()];
+			return new DataResponse($message, Http::STATUS_NOT_FOUND);
+		}
+	}
+
+	/**
+	 * Get all relation data for a view
+	 *
+	 * @param int $viewId View ID
+	 * @return DataResponse<Http::STATUS_OK, array<string, array<string, array{id: int, label: string}>>, array{}>|DataResponse<Http::STATUS_FORBIDDEN|Http::STATUS_INTERNAL_SERVER_ERROR|Http::STATUS_NOT_FOUND, array{message: string}, array{}>
+	 *
+	 * 200: Relation data returned
+	 * 403: No permissions
+	 * 404: Not found
+	 */
+	#[NoAdminRequired]
+	#[NoCSRFRequired]
+	#[CORS]
+	#[RequirePermission(permission: Application::PERMISSION_READ, type: Application::NODE_TYPE_VIEW, idParam: 'viewId')]
+	public function indexViewRelations(int $viewId): DataResponse {
+		try {
+			return new DataResponse($this->relationService->getRelationsForView($viewId));
+		} catch (PermissionError $e) {
+			$this->logger->warning('A permission error occurred: ' . $e->getMessage(), ['exception' => $e]);
+			$message = ['message' => $e->getMessage()];
+			return new DataResponse($message, Http::STATUS_FORBIDDEN);
+		} catch (InternalError $e) {
+			$this->logger->error('An internal error or exception occurred: ' . $e->getMessage(), ['exception' => $e]);
+			$message = ['message' => $e->getMessage()];
+			return new DataResponse($message, Http::STATUS_INTERNAL_SERVER_ERROR);
+		} catch (NotFoundError $e) {
+			$this->logger->info('A not found error occurred: ' . $e->getMessage(), ['exception' => $e]);
+			$message = ['message' => $e->getMessage()];
+			return new DataResponse($message, Http::STATUS_NOT_FOUND);
+		}
+	}
+
 	/**
 	 * Create a column
 	 *
 	 * @param int|null $tableId Table ID
 	 * @param int|null $viewId View ID
 	 * @param string $title Title
-	 * @param 'text'|'number'|'datetime'|'select'|'usergroup' $type Column main type
+	 * @param 'text'|'number'|'datetime'|'select'|'usergroup'|'relation'|'relation_lookup' $type Column main type
 	 * @param string|null $subtype Column sub type
 	 * @param bool $mandatory Is the column mandatory
 	 * @param string|null $description Description
@@ -1572,7 +1640,7 @@ public function createTableShare(int $tableId, string $receiver, string $receive
 	 *
 	 * @param int $tableId Table ID
 	 * @param string $title Title
-	 * @param 'text'|'number'|'datetime'|'select'|'usergroup' $type Column main type
+	 * @param 'text'|'number'|'datetime'|'select'|'usergroup'|'relation'|'relation_lookup' $type Column main type
 	 * @param string|null $subtype Column sub type
 	 * @param bool $mandatory Is the column mandatory
 	 * @param string|null $description Description

lib/Db/Column.php

@@ -100,6 +100,8 @@ class Column extends EntitySuper implements JsonSerializable {
 	public const TYPE_NUMBER = 'number';
 	public const TYPE_DATETIME = 'datetime';
 	public const TYPE_USERGROUP = 'usergroup';
+	public const TYPE_RELATION = 'relation';
+	public const TYPE_RELATION_LOOKUP = 'relation_lookup';
 
 	public const SUBTYPE_DATETIME_DATE = 'date';
 	public const SUBTYPE_DATETIME_TIME = 'time';

lib/Db/Row2Mapper.php

@@ -58,6 +58,9 @@ public function delete(Row2 $row): Row2 {
 		$this->db->beginTransaction();
 		try {
 			foreach ($this->columnsHelper->columns as $columnType) {
+				if ($this->isVirtualColumn($columnType)) {
+					continue;
+				}
 				$this->getCellMapperFromType($columnType)->deleteAllForRow($row->getId());
 			}
 			$this->rowSleeveMapper->deleteById($row->getId());
@@ -195,6 +198,8 @@ public function findAll(array $showColumnIds, int $tableId, ?int $limit = null,
 	private function getRows(array $rowIds, array $columnIds): array {
 		$qb = $this->db->getQueryBuilder();
 
+		$columnIds = $this->addRelationColumnIdsForSupplementColumns($columnIds);
+
 		$qbSqlForColumnTypes = null;
 		foreach ($this->columnsHelper->columns as $columnType) {
 			$qbTmp = $this->db->getQueryBuilder();
@@ -210,6 +215,9 @@ private function getRows(array $rowIds, array $columnIds): array {
 				$qbTmp->selectAlias($qbTmp->createFunction('NULL'), 'value_type');
 			}
 
+			if ($this->isVirtualColumn($columnType)) {
+				continue;
+			}
 			$qbTmp
 				->from('tables_row_cells_' . $columnType)
 				->where($qb->expr()->in('column_id', $qb->createNamedParameter($columnIds, IQueryBuilder::PARAM_INT_ARRAY, ':columnIds')))
@@ -798,6 +806,10 @@ private function insertCell(int $rowId, int $columnId, $value, ?string $lastEdit
 			throw new InternalError(get_class($this) . ' - ' . __FUNCTION__ . ': ' . $e->getMessage());
 		}
 
+		if ($this->isVirtualColumn($column->getType())) {
+			return;
+		}
+
 		// insert new cell
 		$cellMapper = $this->getCellMapper($column);
 
@@ -836,6 +848,10 @@ private function insertCell(int $rowId, int $columnId, $value, ?string $lastEdit
 	 * @throws InternalError
 	 */
 	private function updateCell(RowCellSuper $cell, RowCellMapperSuper $mapper, $value, Column $column): void {
+		if ($this->isVirtualColumn($column->getType())) {
+			return;
+		}
+
 		$this->getCellMapper($column)->applyDataToEntity($column, $cell, $value);
 		$this->updateMetaData($cell);
 		$mapper->updateWrapper($cell);
@@ -846,6 +862,9 @@ private function updateCell(RowCellSuper $cell, RowCellMapperSuper $mapper, $val
 	 */
 	private function insertOrUpdateCell(int $rowId, int $columnId, $value): void {
 		$column = $this->columnMapper->find($columnId);
+		if ($this->isVirtualColumn($column->getType())) {
+			return;
+		}
 		$cellMapper = $this->getCellMapper($column);
 		try {
 			if ($cellMapper->hasMultipleValues()) {
@@ -872,6 +891,9 @@ private function getCellMapper(Column $column): RowCellMapperSuper {
 	}
 
 	private function getCellMapperFromType(string $columnType): RowCellMapperSuper {
+		if ($this->isVirtualColumn($columnType)) {
+			throw new InternalError('Virtual columns do not have cell mappers');
+		}
 		$cellMapperClassName = 'OCA\Tables\Db\RowCell' . ucfirst($columnType) . 'Mapper';
 		/** @var RowCellMapperSuper $cellMapper */
 		try {
@@ -893,6 +915,9 @@ private function getColumnDbParamType(Column $column): int {
 	 * @throws InternalError
 	 */
 	public function deleteDataForColumn(Column $column): void {
+		if ($this->isVirtualColumn($column->getType())) {
+			return;
+		}
 		try {
 			$this->getCellMapper($column)->deleteAllForColumn($column->getId());
 		} catch (Exception $e) {
@@ -961,6 +986,9 @@ private function getFormattedDefaultValue(Column $column) {
 			case Column::TYPE_USERGROUP:
 				$defaultValue = $this->getCellMapper($column)->filterValueToQueryParam($column, $column->getUsergroupDefault());
 				break;
+			case Column::TYPE_RELATION_LOOKUP:
+				$defaultValue = null;
+				break;
 		}
 		return $defaultValue;
 	}
@@ -988,4 +1016,29 @@ private function sortRowsByIds(array $rows, array $wantedRowIds): array {
 
 		return $sortedRows;
 	}
+
+	public function isVirtualColumn(string $columnType): bool {
+		return $columnType === Column::TYPE_RELATION_LOOKUP;
+	}
+
+	/**
+	 * @param int[] $columnIds
+	 * @return int[]
+	 */
+	public function addRelationColumnIdsForSupplementColumns(array $columnIds): array {
+		$allColumns = $this->columnMapper->findAll($columnIds);
+		foreach ($allColumns as $column) {
+			if ($column->getType() !== Column::TYPE_RELATION_LOOKUP) {
+				continue;
+			}
+
+			$customSettings = $column->getCustomSettingsArray();
+			$relationColumnId = $customSettings['relationColumnId'] ?? null;
+			if ($relationColumnId && !in_array($relationColumnId, $columnIds)) {
+				$columnIds[] = $relationColumnId;
+			}
+		}
+		return $columnIds;
+	}
+
 }

lib/Db/RowCellRelation.php

@@ -0,0 +1,23 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * SPDX-FileCopyrightText: 2026 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+namespace OCA\Tables\Db;
+
+/** @template-extends RowCellSuper<RowCellRelation> */
+class RowCellRelation extends RowCellSuper {
+	protected ?int $value = null;
+
+	public function __construct() {
+		parent::__construct();
+		$this->addType('value', 'integer');
+	}
+
+	public function jsonSerialize(): array {
+		return parent::jsonSerializePreparation($this->value);
+	}
+}

lib/Db/RowCellRelationMapper.php

@@ -0,0 +1,40 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * SPDX-FileCopyrightText: 2026 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+namespace OCA\Tables\Db;
+
+use OCP\DB\QueryBuilder\IQueryBuilder;
+use OCP\IDBConnection;
+
+/** @template-extends RowCellMapperSuper<RowCellRelation, int|null, int|null> */
+class RowCellRelationMapper extends RowCellMapperSuper {
+	protected string $table = 'tables_row_cells_relation';
+
+	public function __construct(IDBConnection $db) {
+		parent::__construct($db, $this->table, RowCellRelation::class);
+	}
+
+	/**
+	 * @inheritDoc
+	 */
+	public function hasMultipleValues(): bool {
+		return false;
+	}
+
+	/**
+	 * @inheritDoc
+	 */
+	public function getDbParamType() {
+		return IQueryBuilder::PARAM_INT;
+	}
+
+	public function formatRowData(Column $column, array $row) {
+		$value = $row['value'];
+		return (int)$value;
+	}
+}

lib/Helper/ColumnsHelper.php

@@ -18,6 +18,8 @@ class ColumnsHelper {
 		Column::TYPE_DATETIME,
 		Column::TYPE_SELECTION,
 		Column::TYPE_USERGROUP,
+		Column::TYPE_RELATION,
+		Column::TYPE_RELATION_LOOKUP,
 	];
 
 	public function __construct(
@@ -30,6 +32,9 @@ public function resolveSearchValue(string $placeholder, string $userId, ?Column
 		if (str_starts_with($placeholder, '@selection-id-')) {
 			return substr($placeholder, 14);
 		}
+		if (str_starts_with($placeholder, '@relation-id-')) {
+			return substr($placeholder, 13);
+		}
 
 		$placeholderParts = explode(':', $placeholder, 2);
 		$placeholderName = ltrim($placeholderParts[0], '@');

lib/Migration/Version002001Date20260109000000.php

@@ -0,0 +1,46 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * SPDX-FileCopyrightText: 2026 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+namespace OCA\Tables\Migration;
+
+use Closure;
+use OCP\DB\ISchemaWrapper;
+use OCP\DB\Types;
+use OCP\Migration\IOutput;
+use OCP\Migration\SimpleMigrationStep;
+
+class Version002001Date20260109000000 extends SimpleMigrationStep {
+	public function changeSchema(IOutput $output, Closure $schemaClosure, array $options): ?ISchemaWrapper {
+		/** @var ISchemaWrapper $schema */
+		$schema = $schemaClosure();
+
+		$changes = $this->createRowValueTable($schema, 'relation', Types::INTEGER);
+		return $changes;
+	}
+
+	private function createRowValueTable(ISchemaWrapper $schema, string $name, string $type): ?ISchemaWrapper {
+		if (!$schema->hasTable('tables_row_cells_' . $name)) {
+			$table = $schema->createTable('tables_row_cells_' . $name);
+			$table->addColumn('id', Types::INTEGER, [
+				'autoincrement' => true,
+				'notnull' => true,
+			]);
+			$table->addColumn('column_id', Types::INTEGER, ['notnull' => true]);
+			$table->addColumn('row_id', Types::INTEGER, ['notnull' => true]);
+			$table->addColumn('value', $type, ['notnull' => false]);
+			$table->addColumn('last_edit_at', Types::DATETIME, ['notnull' => true]);
+			$table->addColumn('last_edit_by', Types::STRING, ['notnull' => true, 'length' => 64]);
+			$table->addIndex(['column_id', 'row_id']);
+			$table->addIndex(['column_id', 'value']);
+			$table->setPrimaryKey(['id']);
+			return $schema;
+		}
+
+		return null;
+	}
+}