src/models/Schema.php
public function getDropTable(TableSchema $table, $indent = 0)
    {
        // Do not run this sql: "drop table `tableName`", it will drop the table that has exists before running "./yii migrate"

        $textIndent = $this->textIndent($indent);
        $tableName = static::removePrefix($table->name, $this->db->tablePrefix);

        $definition = <<<DEFINITION
{$textIndent}foreach (\$this->runSuccess as \$keyName => \$value) {
{$textIndent}    if ('createTable' === \$keyName) {
{$textIndent}        \$this->dropTable('{{%$tableName}}');
{$textIndent}    } elseif ('addTableComment' === \$keyName) {
{$textIndent}        \$this->dropCommentFromTable('{{%$tableName}}');
{$textIndent}    } else {
{$textIndent}        throw new \yii\db\Exception('only support "dropTable" and "dropCommentFromTable"');
{$textIndent}    }
{$textIndent}}
DEFINITION;

        return $definition;

    }
public function getDropTable(TableSchema $table, $indent = 0)
    {
        // Do not run this sql: "drop table `tableName`", it will drop the table that has exists before running "./yii migrate"

        $textIndent = $this->textIndent($indent);
        $tableName = static::removePrefix($table->name, $this->db->tablePrefix);

        $definition = <<<DEFINITION
{$textIndent}foreach (\$this->runSuccess as \$keyName => \$value) {
{$textIndent}    if ('createTable' === \$keyName) {
{$textIndent}        \$this->dropTable('{{%$tableName}}');
{$textIndent}    } elseif ('addTableComment' === \$keyName) {
{$textIndent}        \$this->dropCommentFromTable('{{%$tableName}}');
{$textIndent}    } else {
{$textIndent}        throw new \yii\db\Exception('only support "dropTable" and "dropCommentFromTable"');
{$textIndent}    }
{$textIndent}}
DEFINITION;

        return $definition;

    }
get table safeDown definition
@param TableSchema $table
@param $indent int text-indent 文本缩进
@return string