framework/db/Command.php
public function createIndex($name, $table, $columns, $unique = false)
    {
        $sql = $this->db->getQueryBuilder()->createIndex($name, $table, $columns, $unique);

        return $this->setSql($sql)->requireTableSchemaRefresh($table);
    }
public function createIndex($name, $table, $columns, $unique = false)
    {
        $sql = $this->db->getQueryBuilder()->createIndex($name, $table, $columns, $unique);

        return $this->setSql($sql)->requireTableSchemaRefresh($table);
    }
Creates a SQL command for creating a new index.
@param string $name the name of the index. The name will be properly quoted by the method.
@param string $table the table that the new index will be created for. The table name will be properly quoted by the method.
@param string|array $columns the column(s) that should be included in the index. If there are multiple columns, please separate them
by commas. The column names will be properly quoted by the method.
@param bool $unique whether to add UNIQUE constraint on the created index.
@return $this the command object itself