what's in a name?

Populate PHP Object Attributes from Database Column Names Dynamically

If you like coding PHP the OOP way then you will often find yourself in the arduous position of needing to populate your object attributes (member variables) from database row data. And you do this again and again and again, and you find it all rather repetitive, which it is. And you don’t fancy looking at an object relational mapping solution for now, but promise yourself you will “Another Time”.

Here it is;

  1. class MyObject {
  2.  function __construct($data = NULL) {
  3.   if ($data) {
  4.    foreach ($data as $ak => $av) {
  5.     eval(“\$this->” . $this->db2Camel($ak) . ” = ‘{$av}’;”);
  6.    }
  7.   }
  8.  }
  9.  
  10.  function db2Camel($str) {
  11.   $str = strtolower($str);
  12.   $parts = explode(‘_’, $str);
  13.   for ($i = 0; $i < count($parts); $i++) {
  14.    if ($i == 0) {
  15.     $parts[$i] = strtolower($parts[$i]);
  16.    } else {
  17.     $parts[$i] = ucfirst($parts[$i]);
  18.    }
  19.   }
  20.   return implode(”, $parts);
  21.  } 
  22. }

This code relies on a number of assumptions. These are, but are probably not limited to;

  1. The data parameter to the constructor is an associative array, depicting a row from the database. 
  2. That the database column names are lowercase, and separated by underscores, e.g. the_column_name
  3. Your attributes will be in camel casing as governed by the db2Camel function
  4. Your attributes will be public as they do not benefit from an explicit declaration of access scope such as private or protected.
  5. You will access the attributes direct on the object, not through get accessors, e.g. $obj->theAttribute
  6. A programmer would not know the attributes that an object contained from reading the code, they would need to understand the constructor’s function and consult the database column names to infer the attribute names.

If you are happy with all those assumptions, then this code might just prove quite handy in expediating the process of population of PHP object attributes dynamically from a database.

by Allistair

This entry was posted on Tuesday, July 3rd, 2007 at 9:27 pm and is filed under Web Development, OOP, PHP. You can follow any responses to this entry through the RSS 2.0 feed. You can skip to the end and leave a response. Pinging is currently not allowed.

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