DataAccess/Queries/QueryBuilder.php

   1 <?php
   2
   3 namespace DataAccess\Queries;
   4
   5 use DataAccess\Queries\IQueryBuilder;
   6
   7 class QueryBuilder implements IQueryBuilder
   8 {
   9     private $_queryString = 'SELECT * FROM %s';
  10
  11     protected $_whereClauses = array();
  12     protected $_limitClause;
  13     protected $_joinClauses = array();
  14
  15     public function buildQuery()
  16     {
  17         $this->applyJoinClauses()
  18              ->applyWhereClauses()
  19              ->applyLimitClause();
  20
  21         return $this->_queryString;
  22     }
  23
  24     public function setBaseQuery($baseQuery)
  25     {
  26         $this->_queryString = $baseQuery;
  27     }
  28
  29     public function where($columnName, $operator, $value)
  30     {
  31         $this->_whereClauses[$columnName] = array('operator' => $operator, 'value' => $value);
  32         return $this;
  33     }
  34
  35     public function limit($start, $end = null)
  36     {
  37         if($end)
  38         {
  39             $this->_limitClause = sprintf(' LIMIT %u,%u', $start, $end);
  40             return $this;
  41         }
  42
  43         $this->_limitClause = sprintf(' LIMIT %u', $start);
  44
  45         return $this;
  46     }
  47
  48     public function join($type, $tableA, $columnA, $tableB, $columnB)
  49     {
  50         $this->_joinClauses[] = sprintf(' %s JOIN %s ON %s.%s = %s.%s', $type, $tableB, $tableA, $columnA, $tableB, $columnB);
  51         return $this;
  52     }
  53
  54     private function applyJoinClauses()
  55     {
  56         foreach($this->_joinClauses as $joinClause)
  57         {
  58             $this->_queryString .= $joinClause;
  59         }
  60
  61         return $this;
  62     }
  63
  64     private function applyWhereClauses()
  65     {
  66         $this->_queryString .= ' WHERE ';
  67
  68         foreach($this->_whereClauses as $columnName => $columnValue)
  69         {
  70             switch(gettype($columnValue['value']))
  71             {
  72                 case 'integer':
  73                     $this->_queryString .= sprintf("%s%s%u", $columnName, $columnValue['operator'], $columnValue['value']) . ' AND ';
  74                     break;
  75                 case 'string':
  76                     $this->_queryString .= sprintf("%s %s '%s'", $columnName, $columnValue['operator'], $columnValue['value']) . ' AND ';
  77                     break;
  78             }
  79
  80         }
  81
  82         $this->_queryString = rtrim($this->_queryString, ' AND ');
  83         return $this;
  84     }
  85
  86     private function applyLimitClause()
  87     {
  88         $this->_queryString .= $this->_limitClause;
  89         return $this;
  90     }
  91
  92 }