src/Database/Schema/RedshiftSchema.php
public function createIndex($name, $table, $columns, $unique = false)
    {
        $cols = [];
        if (is_string($columns)) {
            $columns = preg_split('/\s*,\s*/', $columns, -1, PREG_SPLIT_NO_EMPTY);
        }
        foreach ($columns as $col) {
            if (strpos($col, '(') !== false) {
                $cols[] = $col;
            } else {
                $cols[] = $this->quoteColumnName($col);
            }
        }
        if ($unique) {
            return
                'ALTER TABLE ' .
                $this->quoteTableName($table) .
                ' ADD CONSTRAINT ' .
                $this->quoteTableName($name) .
                ' UNIQUE (' .
                implode(', ', $cols) .
                ')';
        } else {
            throw new BadRequestException('Indexes not supported.');
        }
    }
public function createIndex($name, $table, $columns, $unique = false)
    {
        $cols = [];
        if (is_string($columns)) {
            $columns = preg_split('/\s*,\s*/', $columns, -1, PREG_SPLIT_NO_EMPTY);
        }
        foreach ($columns as $col) {
            if (strpos($col, '(') !== false) {
                $cols[] = $col;
            } else {
                $cols[] = $this->quoteColumnName($col);
            }
        }
        if ($unique) {
            return
                'ALTER TABLE ' .
                $this->quoteTableName($table) .
                ' ADD CONSTRAINT ' .
                $this->quoteTableName($name) .
                ' UNIQUE (' .
                implode(', ', $cols) .
                ')';
        } else {
            throw new BadRequestException('Indexes not supported.');
        }
    }
Builds a SQL statement 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  $columns the column(s) that should be included in the index. If there are multiple columns,
please separate them by commas. Each column name will be properly quoted by the method,
unless a parenthesis is found in the name.
@param boolean $unique  whether to add UNIQUE constraint on the created index.
@return string the SQL statement for creating a new index.
@throws BadRequestException