application/helpers/sql.php

   1 <?php defined('SYSPATH') OR die('No direct access allowed.');
   2 /**
   3  * SQL Help class
   4  */
   5 class sql_Core
   6 {
   7         /**
   8          * Parse the limit string and split into
   9          * more sql standard LIMIT (val) OFFSET (val)
  10          */
  11         public function limit_parse($str)
  12         {
  13                 $str = trim($str);
  14                 if (empty($str))
  15                         return false;
  16                 $limit_str = false;
  17                 if (strstr($str, ',')) {
  18                         $limit_parts = explode(',', $str);
  19                         if (!empty($limit_parts) && count($limit_parts)==2) {
  20                                 $limit = $limit_parts[1];
  21                                 $offset = $limit_parts[0];
  22                                 $limit_str = " LIMIT ".$limit." OFFSET ".$offset;
  23                         }
  24                 } elseif(is_numeric($str)) {
  25                         $limit_str = !empty($str) ? ' LIMIT '.(int)$str : '';
  26                 }
  27
  28                 return $limit_str;
  29         }
  30
  31         /**
  32         *       Concatenate arguments for use in sql query
  33         *       Since we are using 3 arguments, this method
  34         *       handles just this and nothing else.
  35         *       Arguments 1 and 3 are assumed to be field names
  36         *       and argument 2 i assumed to be a string.
  37         */
  38         public static function concat($arg1, $arg2, $arg3)
  39         {
  40                 switch (Kohana::config('database.default.connection.type'))
  41                 {
  42                         case 'mysql':
  43                                 return " CONCAT(".$arg1.", '".$arg2."', ".$arg3.") ";
  44                                 break;
  45                         default:
  46                                 return " ".$arg1."||'".$arg2."'||".$arg3." ";
  47                 }
  48         }
  49
  50         /**
  51          * Given one SQL function F and N elements E, return (E_0) F (E_1) F (E_2) F ... (E_N)
  52          * Handles empty arguments just fine.
  53          * Is helpful for ANDing or ORing long expressions without having to resort to hacks like
  54          * WHERE 1=1
  55          */
  56         public static function combine() {
  57                 $args = func_get_args();
  58                 $function = array_shift($args);
  59                 $res = false;
  60                 foreach ($args as $arg) {
  61                         if (!empty($arg))
  62                                 $res[] = $arg;
  63                 }
  64                 if (!empty($res))
  65                         $res = '(' . implode(') '.$function.' (', $res) . ')';
  66                 return $res;
  67         }
  68 }
  69