Move schema part to the index

In SQLite, creating an index in another schema is done by prepending the
index name with the schema, while the table name must be unprefixed.

psalm.xml.dist

@@ -326,6 +326,7 @@
                 <referencedMethod name="Doctrine\DBAL\Platforms\SQLServerPlatform::getListTableForeignKeysSQL"/>
                 <referencedMethod name="Doctrine\DBAL\Platforms\SQLServerPlatform::getListTableIndexesSQL"/>
                 <referencedMethod name="Doctrine\DBAL\Platforms\SQLServerPlatform::getListTableMetadataSQL"/>
+                <referencedMethod name="Doctrine\DBAL\Platforms\SqlitePlatform::disableSchemaEmulation"/>
                 <referencedMethod name="Doctrine\DBAL\Platforms\SqlitePlatform::getListTableColumnsSQL"/>
                 <referencedMethod name="Doctrine\DBAL\Platforms\SqlitePlatform::getListTableForeignKeysSQL"/>
                 <referencedMethod name="Doctrine\DBAL\Platforms\SqlitePlatform::getListTableIndexesSQL"/>

src/Platforms/SqlitePlatform.php

@@ -18,6 +18,7 @@
 use Doctrine\DBAL\Types;
 use Doctrine\DBAL\Types\IntegerType;
 use Doctrine\Deprecations\Deprecation;
+use InvalidArgumentException;
 
 use function array_combine;
 use function array_keys;
@@ -26,12 +27,14 @@
 use function array_unique;
 use function array_values;
 use function count;
+use function explode;
 use function implode;
 use function is_numeric;
 use function sprintf;
 use function sqrt;
 use function str_replace;
 use function strlen;
+use function strpos;
 use function strtolower;
 use function trim;
 
@@ -918,6 +921,48 @@ public function getCreateTablesSQL(array $tables): array
         return $sql;
     }
 
+    /**
+     * {@inheritDoc}
+     */
+    public function getCreateIndexSQL(Index $index, $table)
+    {
+        if ($table instanceof Table) {
+            Deprecation::trigger(
+                'doctrine/dbal',
+                'https://github.com/doctrine/dbal/issues/4798',
+                'Passing $table as a Table object to %s is deprecated. Pass it as a quoted name instead.',
+                __METHOD__,
+            );
+
+            $table = $table->getQuotedName($this);
+        }
+
+        $name    = $index->getQuotedName($this);
+        $columns = $index->getColumns();
+
+        if (strpos($table, '.') !== false) {
+            [$schema, $table] = explode('.', $table);
+            $name             = $schema . '.' . $name;
+        }
+
+        if (count($columns) === 0) {
+            throw new InvalidArgumentException(sprintf(
+                'Incomplete or invalid index definition %s on table %s',
+                $name,
+                $table,
+            ));
+        }
+
+        if ($index->isPrimary()) {
+            return $this->getCreatePrimaryKeySQL($index, $table);
+        }
+
+        $query  = 'CREATE ' . $this->getCreateIndexSQLFlags($index) . 'INDEX ' . $name . ' ON ' . $table;
+        $query .= ' (' . $this->getIndexFieldDeclarationListSQL($index) . ')' . $this->getPartialIndexSQL($index);
+
+        return $query;
+    }
+
     /**
      * {@inheritDoc}
      */

tests/Functional/Platform/OtherSchemaTest.php

@@ -0,0 +1,37 @@
+<?php
+
+namespace Doctrine\DBAL\Tests\Functional\Platform;
+
+use Doctrine\DBAL\DriverManager;
+use Doctrine\DBAL\Platforms\SqlitePlatform;
+use Doctrine\DBAL\Schema\Table;
+use Doctrine\DBAL\Tests\FunctionalTestCase;
+use Doctrine\DBAL\Types\Types;
+
+class OtherSchemaTest extends FunctionalTestCase
+{
+    public function testATableCanBeCreatedInAnotherSchema(): void
+    {
+        $databasePlatform = $this->connection->getDatabasePlatform();
+        if (! ($databasePlatform instanceof SqlitePlatform)) {
+            self::markTestSkipped('This test requires SQLite');
+        }
+
+        $this->connection->executeStatement("ATTACH DATABASE '/tmp/test_other_schema.sqlite' AS other");
+        $databasePlatform->disableSchemaEmulation();
+
+        $table = new Table('other.test_other_schema');
+        $table->addColumn('id', Types::INTEGER);
+        $table->addIndex(['id']);
+
+        $this->dropAndCreateTable($table);
+        $this->connection->insert('other.test_other_schema', ['id' => 1]);
+
+        self::assertEquals(1, $this->connection->fetchOne('SELECT COUNT(*) FROM other.test_other_schema'));
+        $connection  = DriverManager::getConnection(
+            ['url' => 'sqlite:////tmp/test_other_schema.sqlite'],
+        );
+        $onlineTable = $connection->createSchemaManager()->introspectTable('test_other_schema');
+        self::assertCount(1, $onlineTable->getIndexes());
+    }
+}

tests/Platforms/SqlitePlatformTest.php

@@ -17,7 +17,10 @@ class SqlitePlatformTest extends AbstractPlatformTestCase
 {
     public function createPlatform(): AbstractPlatform
     {
-        return new SqlitePlatform();
+        $platform =  new SqlitePlatform();
+        $platform->disableSchemaEmulation();
+
+        return $platform;
     }
 
     public function getGenerateTableSql(): string