Smart eager loading

src/AbstractTDBMObject.php

@@ -22,8 +22,11 @@
  */
 
 use JsonSerializable;
+use TheCodingMachine\TDBM\QueryFactory\SmartEagerLoad\Query\PartialQuery;
+use TheCodingMachine\TDBM\QueryFactory\SmartEagerLoad\StorageNode;
 use TheCodingMachine\TDBM\Schema\ForeignKeys;
 use TheCodingMachine\TDBM\Utils\ManyToManyRelationshipPathDescriptor;
+use function array_combine;
 
 /**
  * Instances of this class represent a "bean". Usually, a bean is mapped to a row of one table.
@@ -77,6 +80,13 @@ abstract class AbstractTDBMObject implements JsonSerializable
      */
     private $manyToOneRelationships = [];
 
+    /**
+     * If this bean originates from a ResultArray, this points back to the result array to build smart eager load queries.
+     *
+     * @var PartialQuery|null
+     */
+    private $partialQuery;
+
     /**
      * Used with $primaryKeys when we want to retrieve an existing object
      * and $primaryKeys=[] if we want a new object.
@@ -113,12 +123,13 @@ public function __construct(?string $tableName = null, array $primaryKeys = [],
      * @param array[]     $beanData    array<table, array<column, value>>
      * @param TDBMService $tdbmService
      */
-    public function _constructFromData(array $beanData, TDBMService $tdbmService): void
+    public function _constructFromData(array $beanData, TDBMService $tdbmService, ?PartialQuery $partialQuery): void
     {
         $this->tdbmService = $tdbmService;
+        $this->partialQuery = $partialQuery;
 
         foreach ($beanData as $table => $columns) {
-            $this->dbRows[$table] = new DbRow($this, $table, static::getForeignKeys($table), $tdbmService->_getPrimaryKeysFromObjectData($table, $columns), $tdbmService, $columns);
+            $this->dbRows[$table] = new DbRow($this, $table, static::getForeignKeys($table), $tdbmService->_getPrimaryKeysFromObjectData($table, $columns), $tdbmService, $columns, $partialQuery);
         }
 
         $this->status = TDBMObjectStateEnum::STATE_LOADED;
@@ -131,11 +142,12 @@ public function _constructFromData(array $beanData, TDBMService $tdbmService): v
      * @param mixed[]     $primaryKeys
      * @param TDBMService $tdbmService
      */
-    public function _constructLazy(string $tableName, array $primaryKeys, TDBMService $tdbmService): void
+    public function _constructLazy(string $tableName, array $primaryKeys, TDBMService $tdbmService, ?PartialQuery $partialQuery): void
     {
         $this->tdbmService = $tdbmService;
+        $this->partialQuery = $partialQuery;
 
-        $this->dbRows[$tableName] = new DbRow($this, $tableName, static::getForeignKeys($tableName), $primaryKeys, $tdbmService);
+        $this->dbRows[$tableName] = new DbRow($this, $tableName, static::getForeignKeys($tableName), $primaryKeys, $tdbmService, [], $partialQuery);
 
         $this->status = TDBMObjectStateEnum::STATE_NOT_LOADED;
     }
@@ -179,7 +191,7 @@ public function _setStatus(string $state): void
     {
         $this->status = $state;
 
-        // The dirty state comes form the db_row itself so there is no need to set it from the called.
+        // The dirty state comes from the db_row itself so there is no need to set it from the called.
         if ($state !== TDBMObjectStateEnum::STATE_DIRTY) {
             foreach ($this->dbRows as $dbRow) {
                 $dbRow->_setStatus($state);
@@ -520,19 +532,29 @@ private function removeManyToOneRelationship(string $tableName, string $foreignK
      *
      * @param string $tableName
      * @param string $foreignKeyName
-     * @param mixed[] $searchFilter
-     * @param string $orderString     The ORDER BY part of the query. All columns must be prefixed by the table name (in the form: table.column). WARNING : This parameter is not kept when there is an additionnal or removal object !
+     * @param array<int, string> $localColumns
+     * @param array<int, string> $foreignColumns
+     * @param string $foreignTableName
+     * @param string $orderString The ORDER BY part of the query. All columns must be prefixed by the table name (in the form: table.column). WARNING : This parameter is not kept when there is an additional or removal object !
      *
      * @return AlterableResultIterator
+     * @throws TDBMException
      */
-    protected function retrieveManyToOneRelationshipsStorage(string $tableName, string $foreignKeyName, array $searchFilter, string $orderString = null) : AlterableResultIterator
+    protected function retrieveManyToOneRelationshipsStorage(string $tableName, string $foreignKeyName, array $localColumns, array $foreignColumns, string $foreignTableName, string $orderString = null) : AlterableResultIterator
     {
         $key = $tableName.'___'.$foreignKeyName;
         $alterableResultIterator = $this->getManyToOneAlterableResultIterator($tableName, $foreignKeyName);
         if ($this->status === TDBMObjectStateEnum::STATE_DETACHED || $this->status === TDBMObjectStateEnum::STATE_NEW || (isset($this->manyToOneRelationships[$key]) && $this->manyToOneRelationships[$key]->getUnderlyingResultIterator() !== null)) {
             return $alterableResultIterator;
         }
 
+        $ids = [];
+        foreach ($foreignColumns as $foreignColumn) {
+            $ids[] = $this->get($foreignColumn, $foreignTableName);
+        }
+
+        $searchFilter = array_combine($localColumns, $ids);
+
         $unalteredResultIterator = $this->tdbmService->findObjects($tableName, $searchFilter, [], $orderString);
 
         $alterableResultIterator->setResultIterator($unalteredResultIterator->getIterator());
@@ -558,6 +580,20 @@ public function discardChanges(): void
         }
 
         $this->_setStatus(TDBMObjectStateEnum::STATE_NOT_LOADED);
+        foreach ($this->dbRows as $row) {
+            $row->disableSmartEagerLoad();
+        }
+        $this->partialQuery = null;
+    }
+
+    /**
+     * Prevents smart eager loading of related entities.
+     * If this bean was loaded through a result iterator, smart eager loading loads all entities of related beans at once.
+     * You can disable it with this function.
+     */
+    public function disableSmartEagerLoad(): void
+    {
+        $this->partialQuery = null;
     }
 
     /**

src/DbRow.php

@@ -21,7 +21,13 @@
  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
  */
 
+use TheCodingMachine\TDBM\QueryFactory\SmartEagerLoad\Query\ManyToOnePartialQuery;
+use TheCodingMachine\TDBM\QueryFactory\SmartEagerLoad\Query\PartialQuery;
+use TheCodingMachine\TDBM\QueryFactory\SmartEagerLoad\StorageNode;
 use TheCodingMachine\TDBM\Schema\ForeignKeys;
+use function array_pop;
+use function count;
+use function var_export;
 
 /**
  * Instances of this class represent a row in a database.
@@ -77,7 +83,7 @@ class DbRow
 
     /**
      * The values of the primary key.
-     * This is set when the object is in "loaded" state.
+     * This is set when the object is in "loaded" or "not loaded" state.
      *
      * @var array An array of column => value
      */
@@ -100,6 +106,10 @@ class DbRow
      * @var ForeignKeys
      */
     private $foreignKeys;
+    /**
+     * @var PartialQuery|null
+     */
+    private $partialQuery;
 
     /**
      * You should never call the constructor directly. Instead, you should use the
@@ -115,11 +125,12 @@ class DbRow
      * @param mixed[] $dbRow
      * @throws TDBMException
      */
-    public function __construct(AbstractTDBMObject $object, string $tableName, ForeignKeys $foreignKeys, array $primaryKeys = array(), TDBMService $tdbmService = null, array $dbRow = [])
+    public function __construct(AbstractTDBMObject $object, string $tableName, ForeignKeys $foreignKeys, array $primaryKeys = array(), TDBMService $tdbmService = null, array $dbRow = [], ?PartialQuery $partialQuery = null)
     {
         $this->object = $object;
         $this->dbTableName = $tableName;
         $this->foreignKeys = $foreignKeys;
+        $this->partialQuery = $partialQuery;
 
         $this->status = TDBMObjectStateEnum::STATE_DETACHED;
 
@@ -175,6 +186,15 @@ public function _setStatus(string $state) : void
         }
     }
 
+    /**
+     * When discarding a bean, we expect to reload data from the DB, not the cache.
+     * Hence, we must disable smart eager load.
+     */
+    public function disableSmartEagerLoad(): void
+    {
+        $this->partialQuery = null;
+    }
+
     /**
      * This is an internal method. You should not call this method yourself. The TDBM library will do it for you.
      * If the object is in state 'not loaded', this method performs a query in database to load the object.
@@ -190,26 +210,43 @@ public function _dbLoadIfNotLoaded(): void
             }
             $connection = $this->tdbmService->getConnection();
 
-            list($sql_where, $parameters) = $this->tdbmService->buildFilterFromFilterBag($this->primaryKeys, $connection->getDatabasePlatform());
+            if ($this->partialQuery !== null) {
+                $this->partialQuery->registerDataLoader($connection);
+
+                // Let's get the data loader.
+                $dataLoader = $this->partialQuery->getStorageNode()->getManyToOneDataLoader($this->partialQuery->getKey());
+
+                if (count($this->primaryKeys) !== 1) {
+                    throw new \RuntimeException('Data-loader patterns only supports primary keys on one column. Table "'.$this->dbTableName.'" has a PK on '.count($this->primaryKeys). ' columns'); // @codeCoverageIgnore
+                }
+                $pks = $this->primaryKeys;
+                $pkId = array_pop($pks);
+
+                $row = $dataLoader->get((string) $pkId);
+            } else {
+                list($sql_where, $parameters) = $this->tdbmService->buildFilterFromFilterBag($this->primaryKeys, $connection->getDatabasePlatform());
 
-            $sql = 'SELECT * FROM '.$connection->quoteIdentifier($this->dbTableName).' WHERE '.$sql_where;
-            $result = $connection->executeQuery($sql, $parameters);
+                $sql = 'SELECT * FROM '.$connection->quoteIdentifier($this->dbTableName).' WHERE '.$sql_where;
+                $result = $connection->executeQuery($sql, $parameters);
 
-            $row = $result->fetch(\PDO::FETCH_ASSOC);
+                $row = $result->fetch(\PDO::FETCH_ASSOC);
 
-            if ($row === false) {
-                throw new TDBMException("Could not retrieve object from table \"$this->dbTableName\" using filter \".$sql_where.\" with data \"".var_export($parameters, true)."\".");
+                $result->closeCursor();
+
+                if ($row === false) {
+                    throw new NoBeanFoundException("Could not retrieve object from table \"$this->dbTableName\" using filter \"$sql_where\" with data \"".var_export($parameters, true). '".');
+                }
             }
 
+
+
             $this->dbRow = [];
             $types = $this->tdbmService->_getColumnTypesForTable($this->dbTableName);
 
             foreach ($row as $key => $value) {
                 $this->dbRow[$key] = $types[$key]->convertToPHPValue($value, $connection->getDatabasePlatform());
             }
 
-            $result->closeCursor();
-
             $this->status = TDBMObjectStateEnum::STATE_LOADED;
         }
     }
@@ -289,7 +326,8 @@ public function getRef(string $foreignKeyName) : ?AbstractTDBMObject
             $fk = $this->foreignKeys->getForeignKey($foreignKeyName);
 
             $values = [];
-            foreach ($fk->getUnquotedLocalColumns() as $column) {
+            $localColumns = $fk->getUnquotedLocalColumns();
+            foreach ($localColumns as $column) {
                 if (!isset($this->dbRow[$column])) {
                     return null;
                 }
@@ -303,10 +341,18 @@ public function getRef(string $foreignKeyName) : ?AbstractTDBMObject
 
             // If the foreign key points to the primary key, let's use findObjectByPk
             if ($this->tdbmService->getPrimaryKeyColumns($foreignTableName) === $foreignColumns) {
-                return $this->tdbmService->findObjectByPk($foreignTableName, $filter, [], true);
+                if ($this->partialQuery !== null && count($foreignColumns) === 1) {
+                    // Optimisation: let's build the smart eager load query we need to fetch more than one object at once.
+                    $newPartialQuery = new ManyToOnePartialQuery($this->partialQuery, $this->dbTableName, $fk->getForeignTableName(), $foreignColumns[0], $localColumns[0]);
+                } else {
+                    $newPartialQuery = null;
+                }
+                $ref = $this->tdbmService->findObjectByPk($foreignTableName, $filter, [], true, null, $newPartialQuery);
             } else {
-                return $this->tdbmService->findObject($foreignTableName, $filter);
+                $ref = $this->tdbmService->findObject($foreignTableName, $filter);
             }
+            $this->references[$foreignKeyName] = $ref;
+            return $ref;
         }
     }
 

src/InnerResultArray.php

@@ -3,7 +3,9 @@
 
 namespace TheCodingMachine\TDBM;
 
-use Doctrine\DBAL\Statement;
+use TheCodingMachine\TDBM\QueryFactory\SmartEagerLoad\ManyToOneDataLoader;
+use TheCodingMachine\TDBM\QueryFactory\SmartEagerLoad\StorageNode;
+use TheCodingMachine\TDBM\QueryFactory\SmartEagerLoad\StorageNodeTrait;
 
 /*
  Copyright (C) 2006-2017 David Négrier - THE CODING MACHINE
@@ -26,8 +28,10 @@
 /**
  * Iterator used to retrieve results. It behaves like an array.
  */
-class InnerResultArray extends InnerResultIterator
+class InnerResultArray extends InnerResultIterator implements StorageNode
 {
+    use StorageNodeTrait;
+
     /**
      * The list of results already fetched.
      *

src/InnerResultIterator.php

@@ -8,6 +8,9 @@
 use Mouf\Database\MagicQuery;
 use Psr\Log\LoggerInterface;
 use Psr\Log\NullLogger;
+use TheCodingMachine\TDBM\QueryFactory\SmartEagerLoad\PartialQueryFactory;
+use TheCodingMachine\TDBM\QueryFactory\SmartEagerLoad\Query\PartialQuery;
+use TheCodingMachine\TDBM\QueryFactory\SmartEagerLoad\StorageNode;
 use TheCodingMachine\TDBM\Utils\DbalUtils;
 
 /*
@@ -65,8 +68,14 @@ class InnerResultIterator implements \Iterator, \Countable, \ArrayAccess
      * @var LoggerInterface
      */
     private $logger;
-
-    protected $count = null;
+    /**
+     * @var PartialQuery|null
+     */
+    private $partialQuery;
+    /**
+     * @var int|null
+     */
+    protected $count;
 
     private function __construct()
     {
@@ -76,7 +85,7 @@ private function __construct()
      * @param mixed[] $parameters
      * @param array[] $columnDescriptors
      */
-    public static function createInnerResultIterator(string $magicSql, array $parameters, ?int $limit, ?int $offset, array $columnDescriptors, ObjectStorageInterface $objectStorage, ?string $className, TDBMService $tdbmService, MagicQuery $magicQuery, LoggerInterface $logger): self
+    public static function createInnerResultIterator(string $magicSql, array $parameters, ?int $limit, ?int $offset, array $columnDescriptors, ObjectStorageInterface $objectStorage, ?string $className, TDBMService $tdbmService, MagicQuery $magicQuery, LoggerInterface $logger, ?PartialQueryFactory $partialQueryFactory): self
     {
         $iterator =  new static();
         $iterator->magicSql = $magicSql;
@@ -90,6 +99,11 @@ public static function createInnerResultIterator(string $magicSql, array $parame
         $iterator->magicQuery = $magicQuery;
         $iterator->databasePlatform = $iterator->tdbmService->getConnection()->getDatabasePlatform();
         $iterator->logger = $logger;
+        $partialQuery = null;
+        if ($iterator instanceof StorageNode && $partialQueryFactory !== null) {
+            $iterator->partialQuery = $partialQueryFactory->getPartialQuery($iterator, $magicQuery, $parameters);
+        }
+
         return $iterator;
     }
 
@@ -236,8 +250,9 @@ public function next()
                         $reflectionClassCache[$actualClassName] = new \ReflectionClass($actualClassName);
                     }
                     // Let's bypass the constructor when creating the bean!
+                    /** @var AbstractTDBMObject $bean */
                     $bean = $reflectionClassCache[$actualClassName]->newInstanceWithoutConstructor();
-                    $bean->_constructFromData($beanData, $this->tdbmService);
+                    $bean->_constructFromData($beanData, $this->tdbmService, $this->partialQuery);
                 }
 
                 // The first bean is the one containing the main table.

src/PageIterator.php

@@ -8,6 +8,7 @@
 use Porpaginas\Page;
 use Psr\Log\LoggerInterface;
 use Psr\Log\NullLogger;
+use TheCodingMachine\TDBM\QueryFactory\SmartEagerLoad\PartialQueryFactory;
 
 /*
  Copyright (C) 2006-2017 David Négrier - THE CODING MACHINE
@@ -49,6 +50,10 @@ class PageIterator implements Page, \ArrayAccess, \JsonSerializable
     private $offset;
     private $columnDescriptors;
     private $magicQuery;
+    /**
+     * @var PartialQueryFactory|null
+     */
+    private $partialQueryFactory;
 
     /**
      * The key of the current retrieved object.
@@ -76,7 +81,7 @@ private function __construct()
      * @param mixed[] $parameters
      * @param array[] $columnDescriptors
      */
-    public static function createResultIterator(ResultIterator $parentResult, string $magicSql, array $parameters, int $limit, int $offset, array $columnDescriptors, ObjectStorageInterface $objectStorage, ?string $className, TDBMService $tdbmService, MagicQuery $magicQuery, int $mode, LoggerInterface $logger): self
+    public static function createResultIterator(ResultIterator $parentResult, string $magicSql, array $parameters, int $limit, int $offset, array $columnDescriptors, ObjectStorageInterface $objectStorage, ?string $className, TDBMService $tdbmService, MagicQuery $magicQuery, int $mode, LoggerInterface $logger, ?PartialQueryFactory $partialQueryFactory): self
     {
         $iterator =  new self();
         $iterator->parentResult = $parentResult;
@@ -91,6 +96,7 @@ public static function createResultIterator(ResultIterator $parentResult, string
         $iterator->magicQuery = $magicQuery;
         $iterator->mode = $mode;
         $iterator->logger = $logger;
+        $iterator->partialQueryFactory = $partialQueryFactory;
         return $iterator;
     }
 
@@ -118,9 +124,9 @@ public function getIterator()
             if ($this->parentResult->count() === 0) {
                 $this->innerResultIterator = InnerResultIterator::createEmpyIterator();
             } elseif ($this->mode === TDBMService::MODE_CURSOR) {
-                $this->innerResultIterator = InnerResultIterator::createInnerResultIterator($this->magicSql, $this->parameters, $this->limit, $this->offset, $this->columnDescriptors, $this->objectStorage, $this->className, $this->tdbmService, $this->magicQuery, $this->logger);
+                $this->innerResultIterator = InnerResultIterator::createInnerResultIterator($this->magicSql, $this->parameters, $this->limit, $this->offset, $this->columnDescriptors, $this->objectStorage, $this->className, $this->tdbmService, $this->magicQuery, $this->logger, $this->partialQueryFactory);
             } else {
-                $this->innerResultIterator = InnerResultArray::createInnerResultIterator($this->magicSql, $this->parameters, $this->limit, $this->offset, $this->columnDescriptors, $this->objectStorage, $this->className, $this->tdbmService, $this->magicQuery, $this->logger);
+                $this->innerResultIterator = InnerResultArray::createInnerResultIterator($this->magicSql, $this->parameters, $this->limit, $this->offset, $this->columnDescriptors, $this->objectStorage, $this->className, $this->tdbmService, $this->magicQuery, $this->logger, $this->partialQueryFactory);
             }
         }