framework/console/controllers/BaseMigrateController.php
public function actionDown($limit = 1)
    {
        if ($limit === 'all') {
            $limit = null;
        } else {
            $limit = (int) $limit;
            if ($limit < 1) {
                throw new Exception('The step argument must be greater than 0.');
            }
        }

        $migrations = $this->getMigrationHistory($limit);

        if (empty($migrations)) {
            $this->stdout("No migration has been done before.\n", Console::FG_YELLOW);

            return ExitCode::OK;
        }

        $migrations = array_keys($migrations);

        $n = count($migrations);
        $this->stdout("Total $n " . ($n === 1 ? 'migration' : 'migrations') . " to be reverted:\n", Console::FG_YELLOW);
        foreach ($migrations as $migration) {
            $this->stdout("\t$migration\n");
        }
        $this->stdout("\n");

        $reverted = 0;
        if ($this->confirm('Revert the above ' . ($n === 1 ? 'migration' : 'migrations') . '?')) {
            foreach ($migrations as $migration) {
                if (!$this->migrateDown($migration)) {
                    $this->stdout("\n$reverted from $n " . ($reverted === 1 ? 'migration was' : 'migrations were') . " reverted.\n", Console::FG_RED);
                    $this->stdout("\nMigration failed. The rest of the migrations are canceled.\n", Console::FG_RED);

                    return ExitCode::UNSPECIFIED_ERROR;
                }
                $reverted++;
            }
            $this->stdout("\n$n " . ($n === 1 ? 'migration was' : 'migrations were') . " reverted.\n", Console::FG_GREEN);
            $this->stdout("\nMigrated down successfully.\n", Console::FG_GREEN);
        }
    }
public function actionDown($limit = 1)
    {
        if ($limit === 'all') {
            $limit = null;
        } else {
            $limit = (int) $limit;
            if ($limit < 1) {
                throw new Exception('The step argument must be greater than 0.');
            }
        }

        $migrations = $this->getMigrationHistory($limit);

        if (empty($migrations)) {
            $this->stdout("No migration has been done before.\n", Console::FG_YELLOW);

            return ExitCode::OK;
        }

        $migrations = array_keys($migrations);

        $n = count($migrations);
        $this->stdout("Total $n " . ($n === 1 ? 'migration' : 'migrations') . " to be reverted:\n", Console::FG_YELLOW);
        foreach ($migrations as $migration) {
            $this->stdout("\t$migration\n");
        }
        $this->stdout("\n");

        $reverted = 0;
        if ($this->confirm('Revert the above ' . ($n === 1 ? 'migration' : 'migrations') . '?')) {
            foreach ($migrations as $migration) {
                if (!$this->migrateDown($migration)) {
                    $this->stdout("\n$reverted from $n " . ($reverted === 1 ? 'migration was' : 'migrations were') . " reverted.\n", Console::FG_RED);
                    $this->stdout("\nMigration failed. The rest of the migrations are canceled.\n", Console::FG_RED);

                    return ExitCode::UNSPECIFIED_ERROR;
                }
                $reverted++;
            }
            $this->stdout("\n$n " . ($n === 1 ? 'migration was' : 'migrations were') . " reverted.\n", Console::FG_GREEN);
            $this->stdout("\nMigrated down successfully.\n", Console::FG_GREEN);
        }
    }
Downgrades the application by reverting old migrations.

For example,

```
yii migrate/down     # revert the last migration
yii migrate/down 3   # revert the last 3 migrations
yii migrate/down all # revert all migrations
```

@param int|string $limit the number of migrations to be reverted. Defaults to 1,
meaning the last applied migration will be reverted. When value is "all", all migrations will be reverted.
@throws Exception if the number of the steps specified is less than 1.

@return int the status of the action execution. 0 means normal, other values mean abnormal.