DataAccess/Queries/QueryConstraints.php

   1 <?php
   2
   3 namespace DataAccess\Queries;
   4
   5 use DataAccess\Queries\IQueryConstraints;
   6
   7 class QueryConstraints implements IQueryConstraints
   8 {
   9     private $_queryString;
  10
  11     protected $_whereClauses = array();
  12     protected $_limitClause;
  13     protected $_joinClause;
  14
  15     public function applyTo($queryString)
  16     {
  17         $this->_queryString = $queryString;
  18
  19         $this->applyJoinClause()
  20              ->applyWhereClauses()
  21              ->applyLimitClause();
  22
  23         return $this->_queryString;
  24     }
  25
  26     public function where($columnName, $operator, $value)
  27     {
  28         $this->_whereClauses[$columnName] = array('operator' => $operator, 'value' => $value);
  29         return $this;
  30     }
  31
  32     public function limit($start, $end = null)
  33     {
  34         if($end)
  35         {
  36             $this->_limitClause = sprintf(' LIMIT %u,%u', $start, $end);
  37             return $this;
  38         }
  39
  40         $this->_limitClause = sprintf(' LIMIT %u', $start);
  41
  42         return $this;
  43     }
  44
  45     public function join($type, $tableA, $columnA, $tableB, $columnB)
  46     {
  47         $this->_joinClause = sprintf(' %s JOIN %s ON %s.%s = %s.%s', $type, $tableB, $tableA, $columnA, $tableB, $columnB);
  48         return $this;
  49     }
  50
  51     private function applyJoinClause()
  52     {
  53         $this->_queryString .= $this->_joinClause;
  54         return $this;
  55     }
  56
  57     private function applyWhereClauses()
  58     {
  59         $this->_queryString .= ' WHERE ';
  60
  61         foreach($this->_whereClauses as $columnName => $columnValue)
  62         {
  63             switch(gettype($columnValue['value']))
  64             {
  65                 case 'integer':
  66                     $this->_queryString .= sprintf("%s%s%u", $columnName, $columnValue['operator'], $columnValue['value']) . ' AND ';
  67                     break;
  68                 case 'string':
  69                     $this->_queryString .= sprintf("%s %s '%s'", $columnName, $columnValue['operator'], $columnValue['value']) . ' AND ';
  70                     break;
  71             }
  72
  73         }
  74
  75         $this->_queryString = rtrim($this->_queryString, ' AND ');
  76         return $this;
  77     }
  78
  79     private function applyLimitClause()
  80     {
  81         $this->_queryString .= $this->_limitClause;
  82         return $this;
  83     }
  84
  85 }