[Chat][Doctrine] Replace row-accumulation in DoctrineDbalMessageStore

src/chat/src/Bridge/Doctrine/CHANGELOG.md

@@ -1,6 +1,11 @@
 CHANGELOG
 =========
 
+0.8
+---
+
+ * [BC BREAK] `DoctrineDbalMessageStore::save()` now upserts a single row instead of inserting a new row on every call; the table schema changed from `(id, messages, added_at)` to `(messages, updated_at)`
+
 0.1
 ---
 

src/chat/src/Bridge/Doctrine/DoctrineDbalMessageStore.php

@@ -12,11 +12,7 @@
 namespace Symfony\AI\Chat\Bridge\Doctrine;
 
 use Doctrine\DBAL\Connection as DBALConnection;
-use Doctrine\DBAL\Platforms\OraclePlatform;
 use Doctrine\DBAL\Schema\ComparatorConfig;
-use Doctrine\DBAL\Schema\Name\Identifier;
-use Doctrine\DBAL\Schema\Name\UnqualifiedName;
-use Doctrine\DBAL\Schema\PrimaryKeyConstraint;
 use Doctrine\DBAL\Schema\Schema;
 use Doctrine\DBAL\Types\Types;
 use Psr\Clock\ClockInterface;
@@ -85,43 +81,61 @@ public function drop(): void
             return;
         }
 
-        $queryBuilder = $this->dbalConnection->createQueryBuilder()
-            ->delete($this->tableName);
-
-        $this->dbalConnection->executeStatement($queryBuilder->getSQL());
+        $this->dbalConnection->executeStatement(
+            $this->dbalConnection->createQueryBuilder()
+                ->delete($this->tableName)
+                ->getSQL()
+        );
     }
 
     public function save(MessageBag $messages): void
     {
-        $queryBuilder = $this->dbalConnection->createQueryBuilder()
-            ->insert($this->tableName)
-            ->values([
-                'messages' => '?',
-                'added_at' => '?',
-            ]);
-
-        $this->dbalConnection->executeStatement($queryBuilder->getSQL(), [
-            $this->serializer->serialize($messages->getMessages(), 'json'),
-            $this->clock->now()->getTimestamp(),
-        ]);
+        $serialized = $this->serializer->serialize($messages->getMessages(), 'json');
+        $now = $this->clock->now()->getTimestamp();
+
+        $rowCount = (int) $this->dbalConnection->executeQuery(
+            $this->dbalConnection->createQueryBuilder()
+                ->select('COUNT(*)')
+                ->from($this->tableName)
+                ->getSQL()
+        )->fetchOne();
+
+        if (0 === $rowCount) {
+            $this->dbalConnection->executeStatement(
+                $this->dbalConnection->createQueryBuilder()
+                    ->insert($this->tableName)
+                    ->values(['messages' => '?', 'updated_at' => '?'])
+                    ->getSQL(),
+                [$serialized, $now],
+            );
+        } else {
+            $this->dbalConnection->executeStatement(
+                $this->dbalConnection->createQueryBuilder()
+                    ->update($this->tableName)
+                    ->set('messages', '?')
+                    ->set('updated_at', '?')
+                    ->getSQL(),
+                [$serialized, $now],
+            );
+        }
     }
 
     public function load(): MessageBag
     {
-        $queryBuilder = $this->dbalConnection->createQueryBuilder()
-            ->select('messages')
-            ->from($this->tableName)
-            ->orderBy('added_at', 'ASC')
-        ;
-
-        $result = $this->dbalConnection->executeQuery($queryBuilder->getSQL());
+        $payload = $this->dbalConnection->executeQuery(
+            $this->dbalConnection->createQueryBuilder()
+                ->select('messages')
+                ->from($this->tableName)
+                ->getSQL()
+        )->fetchAssociative();
+
+        if (false === $payload) {
+            return new MessageBag();
+        }
 
-        $messages = array_map(
-            fn (array $payload): array => $this->serializer->deserialize($payload['messages'], MessageInterface::class.'[]', 'json'),
-            $result->fetchAllAssociative(),
+        return new MessageBag(
+            ...$this->serializer->deserialize($payload['messages'], MessageInterface::class.'[]', 'json'),
         );
-
-        return new MessageBag(...array_merge(...$messages));
     }
 
     private function addTableToSchema(Schema $currentSchema): Schema
@@ -130,31 +144,8 @@ private function addTableToSchema(Schema $currentSchema): Schema
 
         $table = $schema->createTable($this->tableName);
         $table->addOption('_symfony_ai_chat_table_name', $this->tableName);
-        $idColumn = $table->addColumn('id', Types::BIGINT)
-            ->setAutoincrement(true)
-            ->setNotnull(true);
-        $table->addColumn('messages', Types::TEXT)
-            ->setNotnull(true);
-        $table->addColumn('added_at', Types::INTEGER)
-            ->setNotnull(true);
-        if (class_exists(PrimaryKeyConstraint::class)) {
-            $table->addPrimaryKeyConstraint(new PrimaryKeyConstraint(null, [
-                new UnqualifiedName(Identifier::unquoted('id')),
-            ], true));
-        } else {
-            $table->setPrimaryKey(['id']);
-        }
-
-        // We need to create a sequence for Oracle and set the id column to get the correct nextval
-        if ($this->dbalConnection->getDatabasePlatform() instanceof OraclePlatform) {
-            $serverVersion = $this->dbalConnection->executeQuery("SELECT version FROM product_component_version WHERE product LIKE 'Oracle Database%'")->fetchOne();
-            if (version_compare($serverVersion, '12.1.0', '>=')) {
-                $idColumn->setAutoincrement(false); // disable the creation of SEQUENCE and TRIGGER
-                $idColumn->setDefault($this->tableName.'_seq.nextval');
-
-                $schema->createSequence($this->tableName.'_seq');
-            }
-        }
+        $table->addColumn('messages', Types::TEXT)->setNotnull(true);
+        $table->addColumn('updated_at', Types::INTEGER)->setNotnull(true);
 
         return $schema;
     }

src/chat/src/Bridge/Doctrine/Tests/DoctrineDbalMessageStoreTest.php

@@ -171,6 +171,21 @@ public function testMessageBagCanBeSaved()
         $this->assertCount(1, $messages);
     }
 
+    public function testSaveOverwritesPreviousMessages()
+    {
+        $connection = DriverManager::getConnection(['driver' => 'pdo_sqlite', 'memory' => true]);
+
+        $messageStore = new DoctrineDbalMessageStore('foo', $connection);
+        $messageStore->setup();
+
+        $messageStore->save(new MessageBag(Message::ofUser('First message')));
+        $messageStore->save(new MessageBag(Message::ofUser('Second message')));
+
+        $messages = $messageStore->load();
+        $this->assertCount(1, $messages);
+        $this->assertSame('Second message', $messages->getUserMessage()->asText());
+    }
+
     public function testMessageBagCanBeLoaded()
     {
         $serializer = new Serializer([