Add migration to fix oracle issues with the database schema

lib/Migration/Version030201Date20201116110353.php

@@ -0,0 +1,60 @@
+<?php
+
+declare(strict_types=1);
+
+namespace OCA\Text\Migration;
+
+use Closure;
+use Doctrine\DBAL\Types\Type;
+use OCP\DB\ISchemaWrapper;
+use OCP\IConfig;
+use OCP\Migration\IOutput;
+use OCP\Migration\SimpleMigrationStep;
+
+class Version030201Date20201116110353 extends SimpleMigrationStep {
+
+	/** @var bool */
+	private $isOracle;
+
+	public function __construct(IConfig $config) {
+		$this->isOracle = $config->getSystemValue('dbtype', 'sqlite') === 'oci';
+	}
+
+	public function changeSchema(IOutput $output, Closure $schemaClosure, array $options) {
+		/** @var ISchemaWrapper $schema */
+		$schema = $schemaClosure();
+
+		$this->ensureColumnIsNullable($schema, 'text_steps', 'version');
+
+		if ($this->isOracle) {
+			// Drop table if we are on oracle and recreate it with the next migration Version030201Date20201116123153
+			if ($schema->hasTable('text_documents')) {
+				$schema->dropTable('text_documents');
+			}
+		} else {
+			$this->ensureColumnIsNullable($schema, 'text_documents', 'current_version');
+			$this->ensureColumnIsNullable($schema, 'text_documents', 'last_saved_version');
+			$table = $schema->getTable('text_documents');
+			$column = $table->getColumn('id');
+			if ($column->getAutoincrement()) {
+				$table->changeColumn('id', [
+					'autoincrement' => false,
+				]);
+			}
+		}
+
+		return $schema;
+	}
+
+	protected function ensureColumnIsNullable(ISchemaWrapper $schema, string $tableName, string $columnName): bool {
+		$table = $schema->getTable($tableName);
+		$column = $table->getColumn($columnName);
+
+		if ($column->getNotnull()) {
+			$column->setNotnull(false);
+			return true;
+		}
+
+		return false;
+	}
+}

lib/Migration/Version030201Date20201116123153.php

@@ -0,0 +1,69 @@
+<?php
+
+declare(strict_types=1);
+
+namespace OCA\Text\Migration;
+
+use Closure;
+use Doctrine\DBAL\Types\Type;
+use OCP\DB\ISchemaWrapper;
+use OCP\IConfig;
+use OCP\Migration\IOutput;
+use OCP\Migration\SimpleMigrationStep;
+
+class Version030201Date20201116123153 extends SimpleMigrationStep {
+
+	/** @var bool */
+	private $isOracle;
+
+	public function __construct(IConfig $config) {
+		$this->isOracle = $config->getSystemValue('dbtype', 'sqlite') === 'oci';
+	}
+
+	public function changeSchema(IOutput $output, Closure $schemaClosure, array $options): ?ISchemaWrapper {
+		if (!$this->isOracle) {
+			return null;
+		}
+
+		/** @var ISchemaWrapper $schema */
+		$schema = $schemaClosure();
+
+		if (!$schema->hasTable('text_documents')) {
+			// Recreate table from the first migration since we cannot alter the autoincrement on the id column with oracle
+			$table = $schema->createTable('text_documents');
+			$table->addColumn('id', Type::BIGINT, [
+				'notnull' => true,
+				'unsigned' => true,
+			]);
+			$table->addColumn('current_version', Type::BIGINT, [
+				// 'notnull' => true,
+				'notnull' => false,
+				'default' => 0,
+				'unsigned' => true,
+			]);
+			$table->addColumn('last_saved_version', Type::BIGINT, [
+				// 'notnull' => true,
+				'notnull' => false,
+				'default' => 0,
+				'unsigned' => true,
+			]);
+			$table->addColumn('last_saved_version_time', Type::BIGINT, [
+				'length' => 20,
+				'unsigned' => true,
+			]);
+			$table->addColumn('last_saved_version_etag', Type::STRING, [
+				'notnull' => false,
+				'length' => 64,
+				'default' => ''
+			]);
+			$table->addColumn('base_version_etag', TYPE::STRING, [
+				'notnull' => false,
+				'length' => 64,
+				'default' => ''
+			]);
+			$table->setPrimaryKey(['id']);
+			return $schema;
+		}
+		return null;
+	}
+}