src/Phossa/Query/Clause/TableConstraintTrait.php
public function constraint(/*# string */ $string)
    {
        if (!isset($this->tbl_constraint['other'])) {
            $this->tbl_constraint['other'] = [];
        }
        $this->tbl_constraint['other'][] = $string;
        return $this;
    }
public function constraint(/*# string */ $string)
    {
        if (!isset($this->tbl_constraint['other'])) {
            $this->tbl_constraint['other'] = [];
        }
        $this->tbl_constraint['other'][] = $string;
        return $this;
    }
Create a constraint

@param  string $string
@return self
@access public